U.S. patent number 10,788,580 [Application Number 15/238,676] was granted by the patent office on 2020-09-29 for position and/or distance measurement, parking and/or vehicle detection, apparatus, networks, operations and/or systems.
This patent grant is currently assigned to SENSYS NETWORKS. The grantee listed for this patent is Luca Fusina, Robert Kavaler. Invention is credited to Luca Fusina, Robert Kavaler.
View All Diagrams
United States Patent |
10,788,580 |
Kavaler , et al. |
September 29, 2020 |
Position and/or distance measurement, parking and/or vehicle
detection, apparatus, networks, operations and/or systems
Abstract
The following are disclosed: Vehicle parking detection, sensors
and an On-Board Device (OBD) to create a parking session. Radars,
microwave antennas, rechargeable power supplies and their power
management circuits. A localized communications protocol between
the wireless nodes and repeaters within a wireless network is
disclosed. Wireless sensors and wireline sensors. The networks
and/or systems may support parking spot management/monitoring,
vehicle traffic analysis and/or management of stationary and/or
moving vehicles, monitor storage areas and/or manage production
facilities. These networks and/or systems may be operated to
generate reports of incorrectly parked vehicles, such as reserved
parking spots for other vehicles, vehicles parked in multiple
parking spots and/or overstaying the time they are permitted to
park.
Inventors: |
Kavaler; Robert (Kensington,
CA), Fusina; Luca (Verona, IT) |
Applicant: |
Name |
City |
State |
Country |
Type |
Kavaler; Robert
Fusina; Luca |
Kensington
Verona |
CA
N/A |
US
IT |
|
|
Assignee: |
SENSYS NETWORKS (Berkeley,
CA)
|
Family
ID: |
1000002383828 |
Appl.
No.: |
15/238,676 |
Filed: |
August 16, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01S
13/0209 (20130101); G08G 1/14 (20130101); G01S
13/931 (20130101); G01S 7/003 (20130101); G01S
7/4004 (20130101); G01S 2013/9314 (20130101) |
Current International
Class: |
G01S
13/93 (20200101); G08G 1/14 (20060101); G01S
13/931 (20200101); G01S 13/02 (20060101); G01S
7/00 (20060101); G01S 7/40 (20060101) |
Field of
Search: |
;342/21 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: McGue; Frank J
Attorney, Agent or Firm: Jennings; Earle
Claims
The invention claimed is:
1. An apparatus, comprising: a parking sensor configured to
determine a parking position of a vehicle in a parking spot;
wherein said vehicle contains, for at least part of the time, an On
Board Device (OBD) configured to present a vehicle identification
in response to said vehicle parking near said parking spot; and
said apparatus further comprising at least one instance of a
superheterodyne radar operated to send a report regarding a sweep
delay for said vehicle, wherein said sweep delay indicates when an
IF signal has a peak amplitude in a sweep in a time for a distance
of said vehicle from an antenna.
2. The apparatus of claim 1, further comprising: a parking
processor configured to generate and/or maintain a parking session
for said vehicle parked in said parking spot, said parking session
including said vehicle identification and an identification of said
parking spot.
3. The apparatus of claim 2, further comprising a parking
management configured to respond to said parking session by
generating and/or maintaining at least one of a parking permit, a
parking payment, a parking reservation, and/or a parking
ticket.
4. The apparatus of claim 3, further comprising at least one of
said OBD implemented by at least one of a cell phone, a tablet
computer, a wearable device, a media player, said vehicle, and/or a
vehicle processor; said parking sensor including at least one of at
least part of an infrared sensor, an ultrasonic sensor and/or a
radar adapted to at least partly determine said parking position;
said parking processor adapted to access and/or include a parking
session memory containing said parking session; and/or said parking
management including at least one management processor configured
to generate and/or maintain at least one of said parking permit,
said parking payment, said parking reservation, and/or said parking
ticket.
5. The apparatus of claim 4, further comprising at least one of
said OBD including at least one of an accelerometer and/or a motion
sensor configured to at least partly indicate said vehicle is
parked; said radar implemented as at least one of a micro-radar
adapted to output less than or equal to ten milliwatts, a Zero
Intermediate Frequency (ZIF) radar, and said superheterodyne
radar.
6. The apparatus of claim 3, further comprising at least one of: a
wireless sensor node and/or a wireline sensor node, each configured
to operate at least one instance of said superheterodyne radar to
send said report regarding said sweep delay; and/or a second
processor configured to receive and to respond to said report by
generating an estimate of said distance of said vehicle from said
superheterodyne radar; and/or an access point configured to
wirelessly communicate with said superheterodyne radar via said
radio transceiver to send a version said report to said processor;
and/or a server configured to communicate said version of said
report from said superheterodyne radar to said processor.
7. The apparatus of claim 6, wherein said wireless sensor node
and/or said wireline sensor node further comprises said processor
coupled to said superheterodyne radar to provide said stimulus.
8. The apparatus of claim 6, wherein at least one of said
processor, said access point, said server and/or said sensor
processor includes at least one instance of at least one of a
finite state machine and a computer accessibly coupled to a memory
containing a program system comprised of program steps configured
to instruct said computer.
9. The apparatus of claim 8, wherein said program system comprises
at least one of the program steps of: operating said
superheterodyne radar to control said compression ratio and said IF
signal; receiving an ADC reading based upon said IF signal and/or
said sweep delay for said object; generating said report based upon
said ADC reading and/or said sweep delay; responding to said report
by sending said version of said report to said second processor;
second responding to said report and/or said version to generate
said distance of said object from said superheterodyne radar; third
responding to said distance of said object from said
superheterodyne radar by updating at least one of a traffic
monitoring system, a traffic control system, a parking management
system, and/or a production management system; second operating
said superheterodyne radar to insure said sweep delay Tm
corresponds to a specific distance T0 of said object; third
operating said superheterodyne radar to generate said IF signal
dominated by a background noise to create a background noise
estimate; using said background noise estimate to adjust a detect
threshold of said object; and/or detecting said object based upon
said ADC reading and said detect threshold.
10. The apparatus of claim 9, wherein the program step of operating
said superheterodyne radar further comprises at least one of the
program steps of controlling a first DAC output and a second DAC
output to generate said sweep delay for said object; setting said
second DAC output to generate said IF signal for said background
noise to dominate; and calibrating said first DAC output to
establish said IF frequency.
11. The apparatus of claim 9, further comprising: at least one of
said traffic monitoring system, said traffic control system, said
parking management system, and/or said production management system
is adapted to communicate with at least one of said superheterodyne
radar, said wireless sensor node, said wireline sensor node, said
second processor, said access point and/or said server.
12. The apparatus of claim 9, wherein said antenna output is
compliant with an Ultra-Wide Band (UWB) signal protocol.
13. The apparatus of claim 9, wherein said IF signal has a
frequency of between 6 Kilo (K) Hertz (Hz) and 7 KHz.
14. The apparatus of claim 9, wherein said compression ratio is
about one million.
15. The apparatus of claim 14, wherein said compression ratio is
one million to within twenty percent.
16. The apparatus of claim 1, wherein said vehicle includes at
least one of a bicycle, a motorcycle, an automobile, a truck, a
bus, a trailer, and/or an aircraft.
Description
CROSS REFERENCE TO RELATED PATENT APPLICATIONS
This application claims priority to
Provisional patent application No. 61/539,909, filed Sep. 27, 2011,
entitled "Solar/Primary Power Apparatus and Method", Provisional
patent application No. 61/581,620 filed Dec. 29, 2011, entitled
"Micro-Radar, Micro-Radar Sensor Nodes, Networks and Systems",
Provisional patent application No. 61/582,157, filed Dec. 30, 2011,
entitled "Wireless and Wireline Sensor Nodes, Micro-Radar, Networks
and Systems", Provisional patent application No. 61/623,044, filed
Apr. 11, 2012, entitled "Micro-Radar, Micro-Radar Sensor Nodes,
Networks and Systems", Provisional patent application No.
61/676,893, filed Jul. 28, 2012, entitled "Micro-Radar, Micro-Radar
Sensor Nodes, Networks and Systems", Provisional patent application
No. 61/669,643, filed Jul. 9, 2012, entitled "Detecting a Parking
Session", Provisional patent application No. 61/671,630, filed Jul.
13, 2012, entitled "Detecting a Parking Session", Provisional
patent application No. 61/676,893, filed Jul. 28, 2012, entitled
"Micro-Radar, Micro-Radar Sensor Nodes, Networks and Systems", and
Provisional patent application No. 61/706,709, filed Sep. 27, 2012,
entitled "Position and/or Distance Measurement, Parking and/or
Vehicle Detection, Apparatus, Networks, Operations and/or Systems",
each which is incorporated herein in their entirety.
TECHNICAL FIELD
This disclosure relates to vehicle parking detection that may
interact with sensors and an On-Board Device (OBD) to create a
parking session. The parking session may identify the vehicle
parked in one or more parking spots. This disclosure also relates
to radars, microwave antennas, rechargeable power supplies and
their power management circuits, that may be used in sensors. The
sensors may operate as nodes in a network. The network may employ
at least one wireline communications protocol and/or at least one
wireless communications protocol. This disclosure also relates to
localized communications protocols between the wireless nodes and
repeaters within a wireless network. The wireless sensors may be
adapted for use in the ground of a parking area and/or parking
strip and/or roadway. Alternatively, sensors may be adapted for
installation into posts, walls, ceilings and/or poles near the
parking spots. The networks and/or systems may support parking spot
management/monitoring, vehicle traffic analysis and/or management
of stationary and/or moving vehicles, monitor storage areas and/or
manage production facilities. These networks and/or systems may be
operated to generate reports of incorrectly parked vehicles, such
as reserved parking spots for other vehicles, vehicles parked in
multiple parking spots and/or overstaying the time they are
permitted to park.
BACKGROUND OF THE INVENTION
There are five areas of technical background affecting this
application: parking system management, radars, antennas, power
management, and wireless communications protocols. Each area has
technical problems discussed below.
Parking System Management:
Sensor-based parking detection systems are becoming increasingly
popular, affordable and economical. These systems can determine
when a vehicle enters a parking spot and when it leaves, but they
cannot detect or identify a specific vehicle in a specific parking
spot. However there are several potential applications that cannot
be supported without knowing which vehicle is in which parking
spot: Parking tickets cannot automatically be generated for an
unidentified vehicle illegally parked in a parking spot. Examples
include a vehicle parked in a parking spot reserved for another, a
vehicle parked in a parking spot whose paid time has run out, a
vehicle parked in the parking spot without paying the parking fee
and a vehicle parked in a spot not designated for parking. Parking
fees cannot be automatically requested for the time the
unidentified vehicle spends parked in the parking spot. Parking
spot reservations cannot be confirmed without knowing the identity
of the vehicle that is parked in the reserved parking spot.
Most parking structures and parking areas have designated parking
spots where drivers should park their vehicles. Often, vehicles are
parked appropriately and with high efficiency, allowing the parking
structure to be optimally used. However, some vehicles may be
parked incorrectly, often taking up more than one parking spot
and/or sticking out into the parking traffic lane. Taking up more
than one parking spot lowers the efficiency of the parking
facility, frustrating other drivers trying to park and lowering the
revenue of the parking facility. Vehicles sticking out into the
parking traffic lane can lead to dangerous situations in which
traffic accidents occur. What is needed is an automated, reliable
process that can note incorrectly parked vehicles and report these
incorrectly parked vehicles to a parking management system and/or
to a parking enforcement authority. The vehicle owner may be
charged more and/or possibly issued a parking ticket.
Regarding Radars:
There has been extensive development of radar since the 1930's for
detecting aircraft and ships at a distance, often over the horizon.
Such systems routinely use many kilowatts to megawatts for
transmitting their radar pulses. What is disclosed herein are
micro-radars that use ten milli-Watts (mW) or less of power to
transmit their pulses. Micro-radars are used to detect vehicles and
determine distances, where the distances involved are typically
within a few meters of the micro-radar. One of the technical
problems with existing micro-radar technology has to do the
difficulties calibrating and maintaining the calibration of a
micro-radar unit. In solving these problems, micro-radars can be
inexpensively implemented and recalibrated throughout the life of a
sensor without human intervention.
Regarding Antennas:
There is extensive literature about microwave antennas. However
only a small fraction of that literature is relevant to
applications involving a microwave antenna interacting with a
transceiver whose active signals are in the range of less than 10
milli-watts. Such microwave antennas will be referred to as having
a micro-power range compatible with the micro-radars of this
disclosure. These antennas are small antennas with a maximum
physical dimension that is less than 7 centimeters (cm). Microwave
antennas tend to have a transmission and reception pattern. This
pattern has lobes all around the antenna when plotted with the
antenna at the center of the plane of maximum transmission power
and receptivity. Microwave antenna components were, and are, very
poor at determining the location of an object, even to the point of
knowing whether it is coming from the left or the right side of the
antenna. The way this problem was solved in large radars was with
the use of a large array of antennas and/or a parabolic reflector,
which changed the lobe pattern to one that dominated a half of the
plane to indicate direction. However, these approaches cannot be
used in small, micro-power antenna applications. There is simply no
room for such approaches. Existing small, micro-power antennas
cannot be used to detect which half of the plane an object is in.
Put another way, they cannot detect whether a vehicle is parked to
the left or the right of a micro-radar sensor. The sensor cannot
tell which of two parking spots 20 is occupied.
Regarding Power Management:
One common prior art configuration of remote power supplies
includes one or more solar cells and rechargeable batteries. Where
there are significant periods of either massive cloud cover or very
little daylight, solar cells may be unable to charge rechargeable
batteries.
Regarding Wireless Communications Protocols:
There are a number of wireless communication protocols, many of
which have successfully implemented hand-off of a moving radio
client or user within a cellular network from one base station to
another. In other applications, a sea of clients, in particular
wireless sensors, may be fixed in location and wirelessly interface
through repeaters to access points. Allocating which wireless
repeater passes on messages from which wireless sensor node to the
access point can be solved with static allocation software, but at
a steep price: These allocations may fail to respond to a changing
wireless environment, such as the parking of a large truck or
container between a wireless sensor and a repeater.
SUMMARY OF THE INVENTION
This patent application discloses embodiments that may be combined
to provide new and improved products and services in a variety of
technical fields. Because of the diversity of applications and
embodiments, a discursive approach is being taken to simplify the
presentation of this disclosure. The discussion will introduce an
application of the various embodiments. After the introductory
discussion each embodiment will then be summarized in turn.
This disclosure begins with the interaction of a vehicle 12
equipped with an On-Board Device (OBD) and at least one sensor
located near or in a parking spot 20. The interaction determines a
parking session for the vehicle 12 parked in the parking spot 20.
The parking session may include a vehicle identification 110 of the
vehicle 12 derived from the interaction with the OBD 100 when the
vehicle 12 is parked, a parking spot 20 identification associated
with the parking spot 20 by the sensor, a starting time 154 and/or
an ending time 156. The ending time 156 may not be set for a
vehicle 12 that is still parked in the parking spot 20. Also, the
starting time 154 may be "swept away" for instance, at
midnight.
In some embodiments, the interaction with the OBD 100 also derives
a responsible operator 112 of the vehicle 12. The responsible
operator 112 may be the vehicle 12's owner, a designated driver,
and/or a manager of the vehicle 12. The responsible operator 112
may be contacted about the vehicle 12's parking, may be responsible
for paying parking tickets 188, parking fees and/or reserving the
parking spot 20.
Here are some examples of the responsible operator 112: In a
family, a husband may be the responsible operator 112 of a first
vehicle 12 and the mother may be the responsible owner of a second
vehicle 12. Continuing the example of a family, a child may operate
a vehicle 12 to which one of the parents is the responsible
operator 112. Alternatively, a child may be going on a long car
trip or to college, and the child may become the responsible
operator 112.
Examples of the OBD 100 include at least one of the following A
cell phone 120 and/or a tablet computer 122 and/or a wearable
device 124 and/or a media player 126 may be operated to implement
the OBD 100. These embodiments may or may not remain in the vehicle
12 once parked and the occupant(s) depart from the vehicle 12. A
vehicle 12 may include the OBD 100 and/or may be configured to
operate as the OBD 100. The vehicle 12 may implement a bicycle, a
motorcycle, a tricycle, an automobile, a truck and/or a
trailer.
The parking session, and the interactions supporting it, may
include determining when and how the vehicle 12 is parked in more
than one parking spot 20. The determination of the vehicle 12
parking in multiple parking spots 20 may involve interactions with
more than one sensor.
The sensor may be adapted for installation on, or in, at least one
of the following: a post or a pole, possibly on or near a street or
lane, a wall and/or a ceiling, possibly as part of a building, such
as a parking facility, and/or a pavement and/or a floor upon which
the vehicle 12 may travel and/or park.
The sensor may be implemented as a wireline sensor and/or a
wireless sensor.
The sensor may include any combination of an infrared sensor, an
ultrasonic sensor and/or a radar. Such sensors may be configured to
operate in accord with the preceding discussion. In particular, the
sensor may include a radar coupled to at least one microwave
antenna. The sensor may be configured to operate the radar and the
microwave antenna to transmit an antenna output. The antenna output
reflects off of the vehicle 12 to create a Radio Frequency (RF)
reflection. The RF reflection is received by the micro-radar. The
sensor uses the received RF reflection to at least partly create a
distance and a direction from the sensor to the vehicle 12.
The microwave antenna may be adapted to form a single sided lobe
pattern with a focused direction. The single sided lobe pattern is
used to generate the direction from the sensor to the vehicle 12.
The sensor may further include the radar coupled via a microwave
switch to the microwave antenna and to a second microwave antenna.
This may provide an advantage of being able to determine parking
sessions 150 for the vehicle 12 in one of several parking spots 20.
The radar may be coupled via the microwave switch to more than two
microwave antennas to determine parking sessions 150 for more than
two parking spots 20.
The radar may be implemented as a micro-radar adapted for small
power outputs less than or equal to 10 milli-watts. In some
implementations of the parking sensors 200, the radar is preferably
implemented as a micro-radar.
The radar may further be implemented as a Zero Intermediate
Frequency (ZIF) radar or a superheterodyne radar including a
Intermediate Frequency (IF) stage in its transmitter and/or its
receiver. The superheterodyne radar may be further implemented as a
homodyne radar that shares a single oscillator with both its
transmitter and receiver.
The superheterodyne radar may include a calibration circuit used to
configure the antenna output and the response to receiving the RF
reflection. This circuit helps address problems one of the
inventors found through laboratory and field testing. Various
embodiments may address some or all of these problems. The prior
art includes a discussion that radar transmission signals in
multi-GigaHertz (GHz) bands are unaffected by changing weather
conditions. While this is true, the prior art overlooks some issues
that the inventor has had to cope with. The inventor has found each
of the following issues to seriously affect at least some
installations of micro-radar: Different manufacturing runs may
alter the operating characteristics of the micro-radar, even in a
laboratory setting. Varying temperature/weather conditions may
alter the operating characteristics. Varying ground conditions for
a micro-radar embedded in the ground may alter the operating
characteristics. The micro-radar components may also drift over
time even when there are little or no changes in the weather or
ground conditions. The component drift may also alter the operating
characteristics. Often, there may be variations in the noise in the
Intermediate Frequency (IF) signal that can compromise the
detection and/or distance estimate. Often, there is a need to
operate the micro-radar in a manner that minimizes power
consumption. For example, in some wireless sensor nodes, there is a
very limited amount of power that can be generated and/or stored by
the wireless sensor node, requiring that a micro-radar use power in
a frugal manner.
The micro-radar may be calibrated response to at least one output
of a Digital to Analog Converter (DAC) and sometimes preferably two
DAC outputs. The DAC output may be used to generate an analog sum
including an exponentially changing signal and the output of the
DAC. Here are two examples of the response of the micro-radar to
distinct analog sums, either or both of which may be incorporated
into the micro-radar and/or its operations: First, the micro-radar
may operate in response to a first analog sum of a first DAC
output, an exponentially changing signal, and a clock pulse. The
response may include generating a receiver mixing signal that is
asserted at a succession of time delays that are a function of the
first analog sum. Second, the micro-radar may be operated based
upon a second analog sum of a second exponentially changing signal
and a second DAC output to control the Intermediate Frequency of
the down converted RF signal. This second sum may control a duty
cycle of a pulse generating oscillator output without changing its
frequency. The duty cycle may be measured as the high time divided
by the period of the oscillator output.
The wireless sensor may be configured to wirelessly communicate
with the access point to at least partly determine the parking
session. Generating the parking session may require that the access
point communicate with more than one sensor. Also, the network may
be generating and/or maintaining multiple parking sessions 150 at
the same time, which will often be based upon communications with
the access point.
The wireless sensor may wirelessly communicate through a repeater
to the access point. The wireless network may include the wireless
sensor and at least two repeaters configured to wirelessly
communicate between the wireless sensor and the access point. The
wireless network may implement a wireless communications protocol.
Messages sent from a wireless sensor may be routed through multiple
repeaters. Sending the same message from multiple repeaters can
cause a message collision at the access point. The sensor and the
repeaters may employ a localized communication scheme to limit
these message collisions.
Consider the following example of a localized communication scheme:
The repeaters may employ a repeater identification code in each
message sent from the repeaters to a wireless sensor to create at
least one received message at the wireless sensor. The wireless
sensor may select one of the received messages to create a selected
repeater identification from the repeater identification code of
the selected received message. The wireless sensor bundles the
selected repeater identification into a sensor message received by
the repeaters. Each repeater examines the sensor message to see if
the selected repeater identification matches its repeater
identification. The repeaters respond to the matching repeater
identifications by transmitting the sensor message to the access
point. This insures that just one repeater sends the sensor
message, thereby avoiding message collisions at the access
point.
The above example is useful in general, but there may situations of
sporadic interference between the repeaters and the access point.
An extension that can address this situation may include the
following steps: The repeaters may employ the repeater
identification code when sending messages to the wireless sensor as
above. The wireless sensor may select more than one of the received
messages to create multiple selected repeater identifications from
the repeater identification code of the selected received messages.
The wireless sensor bundles the selected repeater identifications
into a sensor message received by the repeaters. Each repeater
examines the sensor message to see if one of the selected repeater
identifications matches its repeater identification. The repeaters
respond to the matching repeater identifications by transmitting
the sensor message to the access point at a time offset from each
other. This insures that just one repeater sends the sensor message
at a time, thereby avoiding message collisions at the access point
and improving the probability of the sensor message being received
at the access point.
The wireless communication protocol may implement at least one, and
sometimes several, of the following communications methods: A
Frequency Division Multiple Access (FDMA) method, whereby the
wireless communications are allocated frequency bands, which may or
may not remain fixed as the wireless network evolves through time.
A Time Division Multiple Access (TDMA) method that multiplexes
wireless communications based upon a shared estimate across the
network of time divisions. An example of a TDMA method may maintain
a global clock count at the access point. The access point may
transmit a clock synchronization message via the repeaters to all
the sensors in the network. Upon receipt by each of the sensors, a
local clock estimate may be updated. The communication to and from
the sensors may be coordinated based upon the global clock count at
the access point and the local clock estimates at the sensors. In
some embodiments, the repeaters may also maintain a local clock
count that may be used to synchronize their transmissions to the
access point and control a time delay in sending transmissions to
specific sensors. A Spread Spectrum method, which may include
implementations of at least one, and possibly more than one, of the
following: A Code Division Multiple Access (CDMA) method uses of
one or more layers of spreading codes. A Frequency Hopping Multiple
Access (FHMA) method uses differing frequencies band over time as
estimated by the global clock count at the access point and the
local clock estimate at the sensor and/or at the repeaters. A Time
Hopping Multiple Access (THMA) method uses differing time offsets
for transmission and/or reception by the access point, the
repeaters and the sensors. An Orthogonal Frequency Division
Multiple access (OFDM) method. The OFDM transmission of a message
may include a Fourier or wavelet modulation of a part of the
message to create a modulated component that is then up converted
and mixed for transmission as an antenna output. The reception of
the message may include an antenna input that is down converted to
generate the modulated component, which is then transformed by the
inverse Fourier or wavelet modulation to generate part of the
received message. Any of these wireless communications methods may
include filtering, signal estimators, error correction encoding
and/or decoding, as well as possibly other forms of encryption.
Examples of the wireless communications protocols may implement
various versions of standards developed and/or maintained by the
Institute of Electrical and Electronic Engineers (IEEE), the China
Communications Standards Association (CCSA), European
Telecommunications Standards Institute (ETSI) and/or Association of
Radio Industries and Businesses (ARIB). Examples of such standards
include the IEEE 802 family of communications protocols, and from
ETSI, the GSM and LTE communications protocols.
Some embodiments of the apparatus may include a Power Control
Circuit (PCC) Power Control Circuit (PCC) supporting the use of a
one-charge battery when a rechargeable battery and/or a
photovoltaic cell are unable to supply electrical power to a load.
Examples of a workload include a radio, a micro-radar, and/or a
processor such as computer.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A to FIG. 4B show some details of the apparatus and method of
monitoring one or more parking spots to create parking sessions
that may be used to manage and/or create parking permits, parking
payments, parking reservations, and/or parking tickets:
FIG. 1A to FIG. 1D show the interaction of a vehicle equipped with
an On-Board Device (OBD) and at least one sensor located near or in
a parking spot 20.
FIG. 1E shows the parking session for the vehicle of FIG. 1C and/or
FIG. 1D that may involve a second parking spot.
FIG. 2A to FIG. 2H shows some examples of apparatus that may be
operated to implement the OBD.
FIG. 3A and FIG. 3B show various examples of installations of the
sensor.
FIG. 3C to FIG. 3F show examples of the sensor implemented as a
wireline sensor and/or a wireless sensor, as well as variations in
the communications networks supporting the interactions of the OBD,
the sensor, one or more processors supporting monitoring the
parking sessions managing parking permits, payments, reservations
and/or tickets based upon the parking sessions.
FIG. 4A and FIG. 4B show examples of the OBD being implemented as
an application, otherwise known as a program system.
FIG. 5A to FIG. 7C show some details of the apparatus and method of
localized communication between repeaters and wireless nodes in a
wireless communications network including an access point.
FIG. 5A to FIG. 5F show an example walkthrough of a localized
communication protocol operating between the repeaters and wireless
nodes, in this case, wireless sensor nodes of a wireless network
configured to use an access point based upon a wireless
communications protocol.
FIG. 6A shows an example of the repeater processor and/or wireless
sensor node communicating with a computer readable memory, a disk
drive, a server and/ort the access point to receive a program
system implementing the localized communications protocol and/or
receive an installation package to install the program system.
FIG. 6B shows an example of the repeater's program system
supporting the localized communication protocol.
FIG. 6C shows an example of the wireless sensor program system
supporting the localized communication protocol.
FIG. 6D to FIG. 6G show some details of the messages found in FIG.
5A to FIG. 6C.
FIG. 7A and FIG. 7B show some details involved in a wireless
communications protocol.
FIG. 7C shows an overall operational description of the localized
communication protocol in terms of repeaters and wireless
nodes.
FIG. 8A to FIG. 8D show some examples of a Power Control Circuit
(PCC) supporting the use of a one-charge battery when a
rechargeable battery and a photovoltaic cell are unable to supply
electrical power to a load.
FIG. 9A to FIG. 9C show examples of the sensor discussed above that
may include any combination of an infrared transceiver (possibly
just its transmitter or receiver), an ultrasonic transceiver and/or
a radar. Such sensors may be configured to operate in accord with
the preceding discussion.
FIG. 9D shows some details of the radar implemented as a
micro-radar, a Zero Intermediate Frequency (ZIF) radar, a
superheterodyne radar. The superheterodyne radar may further be
implemented as a homodyne radar that shares an oscillator between
its transmitter and receiver.
FIG. 10A shows a refinement of the sensor of FIG. 9C including a
radar coupled to at least one microwave antenna with a
transmission/reception pattern as shown in FIG. 10B. The parking
sensor will be position at the center of the polar coordinate grid
throughout this disclosure. The transmission/reception pattern may
dominate one half the plane of transmission, which will be referred
to as the half plane. Dominating the half plane supports the
parking sensor distinguishing between vehicles parked in adjacent
parking spots.
FIG. 11A and FIG. 11B show examples of sensor implementations with
a wireline and a wireless network communications interfaces,
respectively. The wireline communications interface may further be
adapted to provide electrical power to the sensor.
FIG. 11C shows an example of the microwave antenna including a
patch antenna and possibly a patch antenna array.
FIG. 11D shows an example of the microwave antenna of FIG. 11C
further including a concave reflector to support shaping the
transmission/reception pattern.
FIG. 11E to FIG. 11J show examples of the microwave antenna
including a microwave injector feeding a horn antenna.
FIG. 12A to FIG. 12D show an example of the sensor including two
microwave antennas that may be configured to separately detect the
first vehicle 12 in the first parking spot 20 and the second
vehicle 12 in the second parking spot 20-2.
FIG. 13A to FIG. 13D show an example of the use of a parking sensor
including four microwave antennas that can determine a vehicle 12
parking in one of four parking spots 20.
FIG. 14 shows a simplified block diagram of an example of the
parking sensor, a wireless sensor node and/or a wireline sensor
node that may include a sensor processor configured to operate a
micro-radar and/or a superheterodyne radar, based upon a first DAC
output and a second DAC output.
FIG. 15A shows a timing diagram of the relationship between the
pulse clock, the transmit signal and the reception signal as
generated by the timing generator and used by the radio frequency
transceiver/mixer (RFTM) of FIG. 14, including the time delay
between the signals and/or the pulses, the pulse widths and duty
cycle.
FIG. 15B shows a timing diagram sweep of the time delay from a
short delay to a long delay over a time interval, as well as the IF
signal over the time interval with a peak amplitude at a sweep
delay Tm corresponding to the distance T0 of the object from the
antenna as shown in FIG. 14.
FIG. 16 shows some details the micro-radar, in particular the
timing generator of FIG. 14, including a transmit control generator
responding to the first DAC output and a reception control
generator responding to the second DAC output.
FIG. 17 shows the first sharp threshold device and/or the second
sharp threshold device of FIG. 16 may include at least one instance
of a logic gate, a comparator and/or a level shifter.
FIG. 18 shows an example of the RFTM of FIG. 14 based upon the
circuitry of U.S. Pat. No. 6,414,627 (hereafter referred to as the
'627 patent).
FIG. 19 shows some examples of the object as at least one of a
person, a bicycle, a motorcycle, an automobile, a truck, a bus, a
trailer and/or an aircraft.
FIG. 20 shows some examples of the object as a surface of a filling
of a chamber.
FIG. 21 shows some other apparatus embodiments that involve the
micro-radar, the superheterodyne radar and/or the homodyne radar of
FIG. 14, including but not limited to, the wireless sensor node and
the wireline sensor node, sending a report based upon the estimate
sweep delay. A processor may respond to the reports to generate an
estimated distance approximating the distance T0 of the microwave
antenna from the object. Access points and/or servers may include
the processor and/or share communications between the sensor nodes
and/or the micro-radars and/or the processors.
FIG. 22 shows some details of at least one of the sensor processor
and/or the processor of FIG. 21 may be individually and/or
collectively may be implemented as one or more instances of a
processor-unit that may include a finite state machine, a computer,
a program system, an inferential engine and/or a neural network.
The apparatus may further include examples of a delivery mechanism,
which may include a computer readable memory, a disk drive and/or a
server, each configured to deliver the program system and/or an
installation package to the processor-unit to implement at least
part of the disclosed method and/or apparatus.
FIG. 23 shows a flowchart of the program system of FIG. 21.
FIG. 24 shows a simplified network diagram of various systems that
may communicate with the micro-radars, the superheterodyne radars,
and/or the homodyne radars, and/or the wireless sensor node and/or
the wireline sensor node and/or the processor and/or the access
point and/or the server of FIG. 21. The various systems include but
are not limited to a traffic monitoring system, a traffic control
system, the parking management system and/or a production
management system.
DETAILED DESCRIPTION OF DRAWINGS
This disclosure relates to the following: Vehicle 12 parking
detection that may interact with sensors and an On-Board Device
(OBD) to create a parking session identifying the vehicle 12 and
one or more parking spots 20 it may be parked in. Micro-radars,
superheterdyne radars and/or homodyne radars, in particular the
calibration and control of the microwave antennas, rechargeable
power supplies and their power management circuits. Communications
protocols between the wireless sensors and repeaters within a
wireless network. The wireless sensors may be adapted for use in
the ground of a parking area and/or parking strip and/or roadway.
Networks and/or systems may support traffic analysis and management
of stationary vehicles 12 and possibly moving vehicles 12. These
networks and/or systems may be operated to generate reports of
vehicles 12 parking incorrectly or in multiple parking spots 20
and/or overstaying the time they are permitted to park.
This patent application discloses embodiments that may be combined
to provide new and improved products and services in a variety of
technical fields. Each technical discussion will begin with a
summary of the Figures involved in the discussion, and then proceed
to discuss those Figures in detail.
FIG. 1A to FIG. 4B show some details of the apparatus and method of
monitoring one or more parking spots 20 to create parking sessions
150 that may be used to manage and/or create parking permits 182,
parking payments 184, parking reservations 186, and/or parking
tickets 188: FIG. 1A to FIG. 1E show the interaction of a vehicle
12 equipped with an On-Board Device (OBD) 100 and at least one
parking sensor 200 located near or in a parking spot 20. FIG. 1F
shows the parking session for the vehicle 12 of FIG. 1C and/or FIG.
1D that may involve a second parking spot 20-2. FIG. 2A to FIG. 2H
shows some examples of apparatus that may be operated to implement
the OBD 100. FIG. 3A and FIG. 3B show various examples of
installations of the parking sensor 200. FIG. 3C to FIG. 3F show
examples of the parking sensor 200 implemented as a wireline sensor
and/or a wireless sensor, as well as variations in the
communications networks supporting the interactions of the OBD 100,
the sensor, one or more processors supporting monitoring the
parking sessions 150 managing parking permits 182, payments,
reservations and/or tickets based upon the parking sessions 150.
FIG. 4A and FIG. 4B show examples of the OBD 100 being implemented
as an application, otherwise known as a program system.
FIG. 1A to FIG. 1E show the interaction of a vehicle 12 equipped
with an On-Board Device (OBD) 100 and at least one parking sensor
200 located near or in a parking spot 20. The interaction
determines a parking session 150 for the vehicle 12 parked in the
parking spot 20.
The parking session 150 may include a vehicle identification 110
110 of the vehicle 12, a parking spot 20 identification 152
associated with the parking spot 20, a starting time 154 and/or an
ending time 156 during which the vehicle 12 is parked in the
parking spot 20. The ending time 156 may not be set for a vehicle
12 that is still parked in the parking spot 20. Also, the starting
time 154 may be "swept away" for instance, at midnight.
In some embodiments, the interaction with the OBD 100 may also
derive a responsible operator 112 of the vehicle 12. The
responsible operator 112 may be associated with the vehicle
identification 110 as shown in FIG. 3C. This association may be
established at a separate time from the parking session 150. The
responsible operator 112 may be the vehicle 12's owner, a
designated driver, and/or a manager of the vehicle 12. The
responsible operator 112 may be contacted by the parking management
180 about the vehicle 12's parking, may be responsible for
obtaining a parking permit 182, paying any parking tickets 188,
making parking payments 184 and/or making a parking reservation 188
for the parking spot 20.
Here are some examples of the responsible operator 112: In a
family, a husband may be the responsible operator 112 of a first
vehicle 12 and the mother may be the responsible operator 112 of a
second vehicle 12. Continuing the example of a family, a child may
operate a vehicle 12 to which one of the parents is the responsible
operator 112. Alternatively, a child may be going on a long car
trip or to college, and the child may become the responsible
operator 112.
Examples of the OBD 100 include at least one of the following The
OBD 100 is configured with a Vehicle IDentifier (ID) 110 within a
region that may be defined by a county, state, province, a parking
service or facility, and/or a cellular phone provider service. The
OBD 100 may be configured to wirelessly communicate with the
parking sensor 200 and/or an access point 350 as shown in FIG. 3E.
The OBD 100 may include an accelerometer 122 as shown in FIG. 3D
and/or a motion detector 120 as shown in FIG. 3C. The OBD 100 may
be configured to determine if the vehicle 12 is stationary or
moving. The OBD 100 may be configured to determine its range from
the parking sensor 200, the access point 350 and/or another OBD 100
to at least partly determine the parking position 130. This
determination may use a wireless communication capability 300-1 of
the OBD 100 as shown in FIG. 3C. A parking processor 170 will refer
to a processor that creates and/or maintains a parking session 150
in a memory referred to as a parking session memory 172. The OBD
100 may be configured to signal a person and/or a processor 170
that a parking session 150 has started as shown in FIG. 2G. The OBD
100 may be configured to display additional information for the
person. That person may be an operator 8 and/or a passenger 6 of
the vehicle 12. The OBD 100 may be configured to receive and
respond to input from the person, who will from hereon be referred
to as a user 10 of the OBD 100.
FIG. 1B shows the vehicle 12 of FIG. 1A with the OBD 100 parked in
the parking spot 20. A parking monitor 160 may interact with the
OBD 100 and the parking sensor 200 to create, update and/or use the
parking session 150. Commonly, the parking monitor 160 may include
at least one parking processor 170 that may include and/or access a
parking session memory 172 containing one or more of the parking
sessions 150. Frequently, the parking session memory 172 may
include at least one non-volatile memory component retaining the
parking session 150 or a version of it, whether or not the parking
session memory 172 loses power. This can support parking management
180 functions such as monitoring parking permits 182, parking
payments 184, parking space reservations 186 and/or at least partly
managing parking tickets 188.
The parking session 150, and the interactions supporting it, may
include determining when and how the vehicle 12 is parked in more
than one parking spot 20. The determination of the vehicle 12
parking in multiple parking spots 20 may involve interactions with
more than one parking sensor 200. The parking session 150 may
further include more than one of the parking spot 20
identifications to indicate that the vehicle 12 is parked in more
than one of the parking spots 20. The determination of the vehicle
12 parking in multiple parking spots 20 may involve interactions
with more than one parking sensor 200 as shown in FIG. 1C and FIG.
1D, and represented by an example of the parking session 150 as
shown in FIG. 1E.
There are several variations of this parking session 150 that are
disclosed and claimed. The ending time 156 may not be set for a
vehicle 12 that is still parked in the parking spot 20. Also, the
starting time 154 may be "swept away" for instance, at
midnight.
A cell phone 120 and/or a tablet computer 122 and/or a wearable
device 124 and/or a media player 126 may be operated to implement
the OBD 100. FIG. 1A shows the vehicle 12 including the OBD 100 and
configured to indicate an identification of the vehicle 12, which
will be referred to herein as the vehicle identification 110. The
vehicle 12 is approaching the parking spot 20 and observed by at
least one parking sensor 200 adapted to at least partly detect the
vehicle 12 and its parking position 130 with respect to the parking
spot 20. At the end of a parking session 150, the vehicle 12 may
depart from the parking spot 20 be reversing the movement of the
vehicle 12 shown in FIG. 1A.
FIG. 2A to FIG. 2H shows some examples of apparatus that may be
operated to implement the OBD 100. FIG. 2A shows a cell phone 120
may implement the OBD 100. FIG. 2B shows a tablet computer 122 may
implement the OBD 100. FIG. 2C shows a wearable device 124 may
implement the OBD 100. FIG. 2D shows a media player 126 may
implement the OBD 100. These embodiments may or may not remain in
the vehicle 12 once parked and the occupant(s) depart from the
vehicle 12.
FIG. 2E shows the vehicle 12 may include the OBD 100 and/or may be
configured to operate as the OBD 100. The vehicle 12 may include a
vehicle processor 180, which may include (as shown) or interact
with a vehicle memory 182 to implement the OBD 100. The vehicle
processor 180 may implement the OBD 100, possibly by executing an
application residing in a vehicle memory 182 as the OBD 100, which
may further interact with wireline and/or wireless communication
devices to identify the vehicle 12 as or when it is parked.
FIG. 2F shows the vehicle 12 may implement a bicycle, a motorcycle,
a tricycle, an automobile, a truck and/or a trailer.
FIG. 2G shows the vehicle 12 may be adapted to at least partly
travel by using a fuel 14 such as gasoline, kerosene, alcohol
and/or diesel contained in a fuel tank 16. Examples of the fuel 14
may include but are not limited to combinations of one or more of
the following: gasoline, alcohol, methane, propane, kerosene,
diesel fuel, and/or biodiesel. The operator 8 may also be
considered a passenger 6. The vehicle 12 may include another one or
more passengers. As used herein, the responsible operator 112 may
or may not be the operator 8 of the vehicle 12. The responsible
operator 112 may be a passenger 6, the owner of the vehicle 12,
and/or a manager of the vehicle 12 for another entity, such as a
vehicle 12 rental company.
FIG. 2H shows the vehicle 12 may be adapted to at least partly
travel based upon electrical power 194, which may be provided solar
cells and/or a recharging station 190 that may be associated with
the parking spot 20. The recharging station 190 may use a charging
cable to deliver the electrical power 194 to the vehicle 12,
possibly by charging its batteries 196. In some embodiments, the
charging cable may also include a communications cable adapted to
communicate with the OBD 100. The vehicle 12 is parked at a parking
spot 20 associated with a recharging station 190 adapted to deliver
electrical power 194 to the battery 196 by a charging cable 192.
The OBD 100 may communicate through the recharging station 190
using a communication cable 193, which may be adapted to interface
to the OBD 100 as an Ethernet or Universal Serial Bus (USB)
connection. The vehicle 12 may include and/or use one or more solar
cells (referred to herein as photovoltaic cells 18) as part of the
recharging station 190, which may be separately plugged in to
provide electrical power 194 to the battery 196.
FIG. 3A and FIG. 3B show various examples of installations of the
parking sensor 200. FIG. 3A shows examples of the parking sensor
200 installed on a post 212 or a pole 210, possibly on or near a
street or lane. FIG. 3B shows the parking sensor 200 installed on,
and/or in, a wall 216-1 and/or 216-2 and/or a ceiling 214, possibly
as part of a building, such as a parking facility, and/or a
pavement 3008 and/or a floor 218 upon which the vehicle 12 may
travel and/or park.
FIG. 3C and FIG. 3D show examples of the parking sensor 200
implemented as a wireline sensor and/or a wireless sensor, as well
as variations in the communications networks supporting the
interactions of the OBD 100, the parking sensor 200, one or more
processors 192, 194, 196, and/or 198 supporting monitoring the
parking sessions 150, managing parking permits 182, parking
payments 184, parking reservations 186 and/or parking tickets 188
based upon the parking sessions 150.
FIG. 3C shows the OBD 100 and the parking sensor 200 wirelessly
communicating with separate access points. The OBD 100 may use a
first wireless communications protocol 300-1 to communicate with
the OBD access point 350. The parking sensor 200 may use a second
wireless communications protocol 300-2 to communicate with the
sensor access point 352. The access points 350 and 352 may use
wireline communications through a parking monitor 160 server to
communicate with at least one parking processor 170 that operates
the parking session memory 172 containing the parking session 150
for the vehicle 12 parked in the parking spot 20. Note that the
access points 350 and 352 may be adapted and/or configured to
respond to differing wireless communications protocols 300-1 and
300-2, respectively. For example, the OBD access point 350 may use
the first wireless communications protocol 300-1, that may
implement a version of IEEE 802.11, WiMax and/or LTE to communicate
wirelessly with the OBD 100. For another example, the sensor access
point 352 may be configured to respond using a second wireless
communications protocol 300-21, possibly compliant with IEEE
802.14.5, M-Bus and/or M2M wireless communications protocols. The
parking monitor 160 may include a parking monitor server 162 that
may further interact using a fourth wireline communications
protocol 302-4 with a parking management server 190 in the parking
management 180.
The parking management server 190 may communicate with a fifth
wireline communications protocol 302-5 in a possibly secured manner
with various processors 192, 194, 196 and/or 198 that may generate
and/or maintain and/or manage parking permits 182, parking payments
184, parking reservations 186 and/or parking tickets 188. A permits
processor 192 may operate upon, create and/or manage the parking
permits 182. A payments processor 194 may operate upon, create
and/or manage the parking payments 184. A reservations processor
196 may operate upon, create and/or manage the parking reservations
186. A tickets processor 198 may operate upon, create and/or manage
the parking tickets 188. Note that in some embodiments, such as
small towns and/or parking facilities, a single processor may
manage all or a combination of the parking permits 182, the parking
payments 184, the parking reservations 186 and/or the parking
tickets 188.
FIG. 3D shows the OBD 100 and the parking sensor 200 communicating
with a single parking monitor server 160 using at least one
wireline communications protocol 330. The parking monitor 160
server may communicate with a parking monitor access point 354 to
communicate with at least one parking processor 170 that operates
the parking session memory 172 containing the parking session 150
for the vehicle 12 parked in the parking spot 20. The parking
monitor access point 354 may also communicate with a parking
monitor access point 354 that communicates in a possibly secured
manner with various processors that may generate and/or maintain
and/or manage parking permits 182, parking payments 184, parking
reservations 186 and/or parking tickets 188.
FIG. 3E shows the parking sensor 200 communicating with the OBD 100
using a sixth wireless communications protocol 300-6, such as a
wireless LAN (WLAN) protocol and/or a form of Bluetooth.
FIG. 3F shows the parking sensor 200 and a vehicle radar 360
included in the vehicle 12 communicating using a radar
communications protocol 330-4, possibly to further determine the
parking position 130 of the vehicle 12 in the parking spot 20.
FIG. 4A and FIG. 4B show examples of the OBD 100 being implemented
as an application, otherwise known as a program system.
FIG. 4A shows that the OBD 100, possibly implemented as part of the
cell phone 120, the tablet computer 122, the wearable device 124,
the media player 126 and/or the vehicle processor 180 may include a
processor-unit 500, an application display 516 and/or a camera 528.
These components may be implemented as one or more instances of a
processor-unit 500 that may include a finite state machine 502, a
computer 504 accessibly coupled 506 to a memory 508 containing an
OBD program system 510. Please note that other finite state
machines, computers coupled to memories will be disclosed herein.
Some of these may have differing reference numbers in part because
they may be separately and possibly independently implemented from
the embodiments related to this or other Figures. The apparatus may
further include examples of a delivery mechanism, which may include
a computer readable memory 530, a disk drive 532, a server 534,
and/or the OBD access point 350, each configured to deliver the OBD
program system 510 and/or an OBD installation package 512 to the
processor-unit 500 to implement at least part of the disclosed
method and/or apparatus of the OBD 100. These delivery mechanisms
may be controlled by an entity directing and/or benefiting from the
delivery to the processor-unit 500, irrespective of where the
server 534 may be located, or the computer readable memory 530 or
disk drive 532 was written.
Several terms will be used throughout this disclosure As used
herein, the Finite State Machine (FSM) 502 and/or 3850 found in
FIG. 22 receives at least one input signal, maintains at least one
state and generates at least one output signal based upon the value
of at least one of the input signals and/or at least one of the
states. As used herein, the computer 504 and/or 3852 includes at
least one instruction processor and at least one data processor
with each of the data processors instructed by at least one of the
instruction processors. At least one of the instruction processors
responds to the program steps of the second program system 2300
residing in the memory 3854. As used herein, the Inferential Engine
3858 includes at least one inferential rule and maintains at least
one fact based upon at least one inference derived from at least
one of the inference rules and factual stimulus and generates at
least one output based upon the facts. As used herein, the neural
network 3860 maintains at list of synapses, each with at least one
synaptic state and a list of neural connections between the
synapses. The neural network 3860 may respond to stimulus of one or
more of the synapses by transfers through the neural connections
that in turn may alter the synaptic states of some of the
synapses.
The OBD 100 may be implemented by a link 518, a button 520, an icon
522 and/or a setup option 524 that when triggered may execute an
OBD installation package 512 that may further operate the OBD 100
to establish the vehicle identification 110 and/or identify the
responsible operator 112, possibly by their cell phone 120 number,
voice print, thumb and/or finger print, and/or by a login
procedure.
As used herein, the application display 516 may or may not be built
into the OBD 100. In some embodiments, it may be viewed by a user
10 in a head-up display, which may be a wearable device 124 and/or
projected onto a viewing surface of the vehicle 12.
The processor-unit 500 may respond to a download image 514 in
response to the camera 528 focused on a download glyph 526, by
delivery of the OBD program system 510 and/or the OBD installation
package 512.
FIG. 4B shows an example of the OBD program system 510 including at
least one of the following program steps: Program step 550 may
support establishing the vehicle identification 110 and/or the
responsible operator 112. Program step 552 may support
communicating the vehicle identification 110 in response to the
vehicle 12 parking. In some embodiments, this may further include
at least one of the following: Program step 554 may support
determining that the vehicle 12 is parking. This program step may
use the motion detector 120 and/or accelerometer 122 of the OBD
100. Program step 556 may support further communicating with the
responsible operator 112. Program step 558 may support
communicating that the vehicle 12 is leaving the parking spot 20.
Program step 560 may support requesting a parking extension for the
vehicle identification 110.
Here begins a discussion of a localized communications protocol 750
outlined in FIG. 7C and represented in a walk through of its
operations and apparatus in FIGS. 5A to 7B. operating between
wireless nodes 380 and repeaters 370 in a wireless network using
access points 360. Such a wireless network may implement one or
more wireless communications protocol 300s, such as the first
wireless communications protocol 300-1 and/or the second wireless
communications protocol 300-2 shown in FIG. 3C, which will be
referred to as a generic wireless communications protocol 700 in
the following Figures.
FIG. 5A to FIG. 7C show some details of the apparatus and method of
localized communication between repeaters 370 and wireless nodes
380 in a wireless communications network including an access point
360. FIG. 5A to FIG. 5F show an example walkthrough of a localized
communication protocol operating between the repeaters 370 and
wireless nodes 380, in this case, wireless sensor nodes of a
wireless network configured to use an access point 360 based upon a
wireless communications protocol 700. FIG. 6A shows an example of
the repeater processor and/or wireless sensor node communicating
with a computer readable memory, a disk drive, a server and/ort the
access point 360 to receive a program system implementing the
localized communications protocol and/or receive an installation
package to install the program system. FIG. 6B shows an example of
the repeaters program system supporting the localized communication
protocol. FIG. 6C shows an example of the wireless sensor program
system supporting the localized communication protocol. FIG. 6D to
FIG. 6G show some details of the messages found in FIG. 5A to FIG.
6C. FIG. 7A and FIG. 7B show some details involved in a wireless
communications protocol 300. FIG. 7C shows an overall operational
description of the localized communication protocol in terms of
repeaters 370 and wireless nodes 380.
FIG. 5A to FIG. 5F show a walkthrough of a localized communication
protocol 750 operating between the repeaters 370 and wireless nodes
380 of a wireless network 362 configured to use an access point 360
based upon at least one wireless communications protocol 700.
FIG. 5A shows a simplified communications diagram of the wireless
network 362 implementing the wireless communications protocol 700
showing message and/or packet and/or frame communications between a
single wireless node 380[1,3] implemented as the parking sensor
200[1,3]. This Figure shows a wireless network 362 as it might be
applied to the parking facilities of a sporting stadium, which
might include one or more hectares of parking spots 20, shown here
as two grids, each including one of parking sensors 200. By way of
example, parking spot 20[1,1] is monitored by the parking sensor
200[1,1]. In a similar fashion, parking spot 20[2,2] is monitored
by the parking sensor 200[2,2], and so on. The wireless node
380[1,3] can communicate with the access point 360 through two
repeaters 370-1 and 370-2.
FIG. 5B shows a further simplified diagram of the wireless
communications of FIG. 5A. In this Figure, the wireless nodes 380
are considered to have a fixed spatial relationship with the
repeaters 370-1 and 370-2. Many network planning systems use these
spatial relationships to allocate repeater services among the
wireless nodes as a fixed service map.
FIG. 5C shows a problem that can arise with the wireless network of
the previous Figures. Suppose that the first repeater 370-1 was
allocated to service messages between the wireless node 380 and the
access point 360. Now suppose that a large vehicle 12 is parked on
or near the wireless node 380, causing the signal path to become
much longer and the signal strength of the wireless communications
between the first repeater 370-1 and the wireless node 380 to
become much weaker. This may make the communications path between
the second repeater 370-2 and the wireless node 380 much more
reliable. But there is no way to predict these occurrences. And the
reallocation of the repeaters 370 servicing the wireless nodes 380
is difficult to perform in real time, in part because there may be
thousands of wireless nodes 380 in a large parking facility.
FIG. 5D shows a more detailed view of the interactions of FIG. 5A
to FIG. 5C in the wireless network 362 implementing the localized
communication protocol 750. The access point 360 may include a
received uplink message 514. How the received uplink message 514
gets to the access point 360 will now be discussed and is shown in
further detail in FIG. 5E. The first repeater 370-1 may include a
first repeater identification 376-1 and the second repeater 370-2
may include a second repeater identification 376-2. These
identifications 376-1 and 376-2 are preferably locally distinct so
that all the repeaters 370 that can wirelessly communicate with the
wireless node 380 can be distinguished by their respective
identifications 376. The wireless node 380 may use a selected
repeater identification 386 to generate an uplink message 508
containing the selected repeater identification 386. The wireless
node 380 may transmit the uplink message 508 through a node
transceiver 384 to the first repeater 370-1 and to the second
repeater 370-2. The first repeater 370-1 may use its first repeater
transceiver 374-1 to create the first received uplink message 510-1
containing the selected repeater identification 386. The second
repeater 370-2 may use its second repeater transceiver 374-2 to
create the second received uplink message 510-2, also containing
the selected repeater identification 386. Each of these repeaters
370-1 and 370-2 operates upon the selected repeater identification
386 and its repeater identification to decide whether to generate
and send its uplink message to the access point 360 to create the
received uplink message 514. The first repeater 370-1 compares the
selected repeater identification 386 to the first repeater
identification 376-1. The first repeater 370-1 sends the first
uplink message 512-1 in response to the selected repeater
identification 386 matching the first repeater identification
376-1. In many implementations, the first uplink message is
generated only when there is a match. In some implementations, the
same buffer may be used for the first received uplink message 510-1
and for the first uplink message 512-1, so that the issue of
generating the first uplink message 512-1 may or may not be
relevant. The second repeater 370-2 sends the second uplink message
512-2 in response to the selected repeater identification 386
matching the second repeater identification 376-2 in a fashion as
discussed for the first repeater 370-1. The access point 360
receives the uplink message from only one of the repeaters through
the use of this localized communications protocol 750. The received
uplink message 514 is received as the first uplink message 512-1
from the first repeater 370-1 when the selected repeater
identification 386 matches the first repeater identification 376-1.
The received uplink message 514 is received as the second uplink
message 512-2 from the second repeater 370-2 when the selected
repeater identification 386 matches the second repeater
identification 376-2. The localized communication protocol 750
insures that the uplink message 508 originates from the wireless
node 380, uses only one repeater 370-1 or 370-2 to transfer the
uplink message to the access point 360.
FIG. 5D, and in particular FIG. 5F, show the access point 360 may
further include a raw downlink message 500 that is to be sent to
the wireless node 380. Consider the following example of how the
raw downlink message 500 may be sent to the wireless node 380: The
first repeater 370-1 receives the raw downlink message 500, which
is used to generate the first repeated downlink message 502-1 that
additionally contains the first repeater identification 376-1. The
first repeater transceiver 374-1 sends the first repeated downlink
message 502-1 to the wireless node 380. The second repeater 370-2
receives the raw downlink message 500, which is used to generate
the second repeated downlink message 502-2 that additionally
contains the second repeater identification 376-2. The second
repeater transceiver 374-2 sends the second repeated downlink
message 502-2 to the wireless node 380. The wireless node 380 may
receive one or more of the repeated downlink messages 502-1 and
502-2. For the moment, let the wireless node 380 receive at least
one downlink message 504 contained a received repeater
identification 506. In some embodiments, the wireless node 380 may
determine the selected repeater identification 386 based upon the
received repeater identifications 506 and/or based upon the quality
of the received downlink messages 504, possibly as consider over a
period of time, such as 10 seconds, a minute or more.
In FIG. 5D to FIG. 5F, each of the repeaters 370-1 and 370-2 is
shown including a repeater processor, which may differ in structure
through the wireless network 362. The potential differences in
structure may not affect the operations of the localized
communications protocol. The first repeater 370-1 may include the
first repeater processor 372-1, which may interact with the first
repeater transceiver 374-1 to wirelessly communicate with the
wireless node 380. The second repeater 370-2 may include the second
repeater processor 372-2, which may interact with the second
repeater transceiver 374-2 to wirelessly communicate with the
wireless node 380. Here is an example of the kinds of structural
differences that may be encountered: The first repeater processor
372-1 may implement the operations of the localized communications
protocol 750 using a finite state machine (FSM) 602 as shown in
FIG. 6A. The second repeater processor 372-2 may implement the
operations of the localized communications protocol 750 using a
computer 604 as shown in FIG. 6A.
The wireless node 380 may include a wireless node processor 382
that may interact with the node transceiver 384 to create the
received downlink message(s) 504 and to send the uplink message
508.
In some embodiments of the localized communications protocol 750,
the selected repeater identification 386 may be determined at the
wireless node processor 382 based upon a wireless node program
system 610 as shown in FIG. 6A. The wireless node program system
610 may have a table of selected repeater identifications 386 that
may be used at different times or in different situations, such as
during a sporting event.
FIG. 6A shows an example of a repeater processor 372 and/or a
wireless node processor 382 communicating with a computer readable
memory 530, a disk drive 532, a server 534 and/or the access point
360 to receive at least one program system 610 and/or 614
implementing the localized communications protocol 750 and/or
receive an installation package 612 and/or 616 to install the
program system. The repeater processor 372 may be shown through the
examples of the first repeater processor 372-1 and/or the second
repeater processor 372-2 of FIG. 5D to FIG. 5F. The repeater
processor 372 and/or the wireless node processor 382 may include a
processor-unit 600. These processor-units may differ between
specific instances of the repeater processors 372 and/or the
wireless node processors 382.
Any instance of the processor-unit 600 may include one or more
instances of the Finite State Machine (FSM) 602 and/or a computer
604 and/or a memory 608. The computer 604 may be accessibly coupled
606 to the memory 608 in some situations. The FSM 602 receives at
least one input signal, maintains at least one state and generates
at least one output signal based upon the value of at least one of
the input signals and/or at least one of the states. As used
herein, the computer 604 includes at least one instruction
processor and at least one data processor with each of the data
processors instructed by at least one of the instruction
processors. At least one of the instruction processors responds to
the program steps of at least one of the program systems 610 and/or
614 residing in the memory 608. As with any memory disclosed
herein, the memory 608 may include a non-volatile component, which
may retain the program system 610 and/or 614 in the event that
electrical power is not supplied to the memory 608. Alternatively,
the memory 608 may require a regular, if not necessarily
continuous, electrical power supply to retain the program system
610 and/or 614.
Regarding the repeater processor 372: The FSM 602 may be configured
by the repeater installation package 616 to implement the repeater
portion 754 and/or 762 of the localized communications protocol 750
as shown and soon to be discussed regarding FIG. 7C. The computer
604 may be instructed by the repeater program system 614 to
implement the repeater portion 754 and/or 762 of the localized
communications protocol 750 as shown and soon to be discussed
regarding FIG. 7C. The repeater installation package 616 may also
instruct the computer 604 to implement the repeater program system
614 in the memory 608 in some embodiments.
Regarding the wireless node processor 382: The FSM 602 may be
configured by the wireless node installation package 612 to
implement the wireless node portion 756 and/or 760 of the localized
communications protocol 750 as shown and soon to be discussed
regarding FIG. 7C. The computer 604 may be instructed by the
wireless node program system 610 to implement the wireless node
portion 756 and/or 760 of the localized communications protocol 750
as shown and soon to be discussed regarding FIG. 7C. The wireless
node installation package 612 may also instruct the computer 604 to
implement the wireless program system 610 in the memory 608 in some
embodiments.
In discussing the operation of the repeaters 370-1 and 370-2 and
the wireless node 380 some details of the messages will be referred
to through the examples provided by FIG. 6D to FIG. 6G.
FIG. 6B shows an example of the repeater program system 614
supporting the repeater portion 754 and/or 762 of the localized
communications protocol 750 as shown and soon to be discussed
regarding FIG. 7C.
Program step 630 supports establishing the repeater identification
376, which in some embodiments may occur once or infrequently. Note
that for the first repeater 370-1, the first repeater
identification 376-1 is established. For the second repeater 370-2,
the second repeater identification 376-2 is established.
Note that the access point 360 sends the raw downlink message 500,
which is received by the repeaters 370-1 and 370-2 as the received
downlink message 501, shown in FIG. 6D. The messages 500 and 501
include a raw downlink payload 503 destined for delivery to the
wireless sensor node 380.
Program step 632 of FIG. 6B supports generating and sending the
repeated downlink message 502 with the repeater identification 376.
This operation may frequently be implemented by two further process
steps: Program step 634 supports packing the repeater
identification 376 into a repeated downlink payload 505 as shown in
FIG. 6E. Program step 636 supports packing the downlink payload of
the received downlink message into the repeated downlink payload.
FIG. 6E shows an example of the first repeated downlink message
502-1 for the first repeater 370-1 as shown in FIG. 5D and FIG. 5E.
The repeated downlink payload 505 includes the first repeater
identification 376-1 and the raw downlink payload 503 of FIG.
6D.
Program step 638 of FIG. 6B supports receiving the uplink message
508 with the selected repeater identification 386 from the wireless
node 380. FIG. 6F shows some details of the uplink message 508, the
first received uplink message 510-1 and the second received uplink
message 510-2. The first repeater 370-1 creates the first received
uplink message 510-1 by receiving the uplink message 508 from the
wireless node 380. The second repeater 370-2 the second received
uplink message 510-2 by receiving the uplink message 508 from the
wireless node 380. Each of the messages 508, 510-1 and 510-2
includes the selected repeater identification 386 and the basic
uplink payload 503.
Program step 640 of FIG. 6B supports generating and sending the
uplink message 512 if the selected repeater identification 386
matches the repeater identification 376. The first repeater 370-1
generates and sends the first uplink message 512-1. The second
repeater 370-2 generates and sends the second uplink message 512-2.
FIG. 6G shows some details of the first uplink message 512-1, the
second uplink message 512-2 and the received uplink message 514,
which indicates that the selected repeater identification 386 has
been stripped from the messages, leaving only the basic uplink
payload 503.
FIG. 6C shows an example of the wireless node program system 610
supporting wireless node 380 operation steps 756 and 760 of the
localized communication protocol 750 as shown in FIG. 7C.
Program step 650 of FIG. 6C supports the wireless sensor node 380
receiving at least one repeated downlink message 502 with a
repeater identification 376 to create a received repeater
identification 388 as shown in FIG. 5D and FIG. 5E. This program
step may further include at least one of the following: Program
step 652 of FIG. 6C supports the wireless sensor node 380
extracting the repeater identification 376 to create the received
repeater identification 388. Program step 654 of FIG. 6C supports
the wireless sensor node 380 unpacking the raw downlink payload
from the repeated downlink message 502. FIG. 6E shows an example of
the first repeater downlink message 502-1 including the first
repeater identification 376-1 and the raw downlink payload, both as
parts of the repeated downlink payload 505. The first repeater
downlink message 502-1 may be generated and send from the first
repeater 370-1 to the wireless node 380 as shown in FIG. 5E.
Program step 656 of FIG. 6C supports the wireless sensor node 380
selecting from the received repeater identifications 388 to create
the selected repeater identification 386.
Program step 658 of FIG. 6C supports the wireless sensor node 380
generating and sending the uplink message 508 with the selected
repeater identification 386. This program step may further include
at least one of the following Program step 660 of FIG. 6C supports
the wireless sensor node 380 packing the selected repeater
identification 386. Program step 662 of FIG. 6C supports the
wireless sensor node 380 generating and packing the basic uplink
payload 503. FIG. 6F shows an example of the uplink message 508
generated and sent by the wireless node 380 as shown in FIG. 5F.
The uplink message 508 is received by the first repeater 370-1 as
the first received uplink message 510-1. The uplink message 508 is
received by the second repeater 370-2 as the second received uplink
message 510-2. The messages 508, 510-1 and 510-2 include the
selected repeater identification 386 and the basic uplink payload
503, which may both be packaged as the repeated uplink payload
507.
FIG. 6D to FIG. 6G show some details of the messages found in FIG.
5A to FIG. 6C which have been discussed with regards to the program
systems 610 and 614 of FIG. 6B and FIG. 6C.
FIG. 7A and FIG. 7B show some details involved in a wireless
communications protocol 300.
FIG. 7A shows the wireless communication protocol 700 may implement
at least one, and sometimes several, of the following
communications methods: A Frequency Division Multiple Access (FDMA)
702 method, whereby the wireless communications are allocated
frequency bands, which may or may not remain fixed as the wireless
network evolves through time. A Time Division Multiple Access
(TDMA) 704 method that multiplexes wireless communications based
upon a shared estimate across the network of time divisions. An
example of a TDMA method may maintain a global clock count at the
access point. The access point may transmit a clock synchronization
message via the repeaters to all the sensors in the network. Upon
receipt by each of the sensors, a local clock estimate may be
updated. The communication to and from the sensors may be
coordinated based upon the global clock count at the access point
and the local clock estimates at the sensors. In some embodiments,
the repeaters may also maintain a local clock count that may be
used to synchronize their transmissions to the access point and
control a time delay in sending transmissions to specific sensors.
A Spread Spectrum method 706, which may include implementations of
at least one, and possibly more than one, of the following: A Code
Division Multiple Access (CDMA) 708 method that uses of one or more
layers of spreading codes. A Frequency Hopping Multiple Access
(FHMA) 710 method that uses differing frequencies band over time as
estimated by the global clock count at the access point and the
local clock estimate at the sensor and/or at the repeaters. A Time
Hopping Multiple Access (THMA) 712 method that uses differing time
offsets for transmission and/or reception by the access point, the
repeaters and the sensors. An Orthogonal Frequency Division
Multiple access (OFDM) 714 method may include the following: The
OFDM transmission of a message may include a Fourier or wavelet
modulation of a part of the message to create a modulated component
that is then up converted and mixed for transmission as an antenna
output. The reception of the message may include an antenna input
that is down converted to generate the modulated component, which
is then transformed by the inverse Fourier or wavelet modulation to
generate part of the received message. Any of these wireless
communications methods may include filtering, signal estimators,
error correction encoding and/or decoding, as well as possibly
other forms of encryption.
FIG. 7B shows that examples of the wireless communications
protocols 700 and/or the wireline communications protocols 730 may
implement various versions of standards developed and/or maintained
by the Institute of Electrical and Electronic Engineers (IEEE) 720,
the China Communications Standards Association (CCSA) 722, European
Telecommunications Standards institute (ETSI) 724 and/or
Association of Radio Industries and Businesses (ARIB) 726. Examples
of such standards include the IEEE 802 family of communications
protocols, and from ETSI 724, the GSM and LTE wireless
communications protocols 700. Examples of the wireline
communications protocols 730 may be used to implement wireline
communications across one or more of following: In FIG. 2H, the
communications cable 193 may implement a form of Universal Serial
Bus (USB) and/or a form of Ethernet, both of which are standards
developed by IEEE (720). In FIG. 3C, the first wireline
communications protocol 302-1, the second wireline communications
protocol 302-2, the third wireline communications protocol 302-3,
the fourth wireline communications protocol 302-4, and/or the fifth
wireline communications protocol 302-5 may implemented as standards
developed and/or maintained by at least one of the organizations of
FIG. 7B. In FIG. 3D, the first wireline communications protocol
330-1 and the second wireline communications 330-2 may interface at
a parking monitor server 162 ion a form of a client server
communications protocol, possibly supporting a TCP-IP stack,
possibly an internet protocol.
FIG. 7C shows an overall operational description of the localized
communication protocol in terms of repeaters 370 and wireless nodes
380. These operations have been discussed throughout the
description of FIG. 5A to FIG. 6G.
FIG. 8A to FIG. 8F show some examples of a Power Control Circuit
(PCC) 800 supporting the use of a one-charge battery 802 when a
rechargeable battery 842 and a photovoltaic cell 840 are unable to
supply electrical power 194 to a load 804.
FIG. 8A shows the PCC 800 including at least two couplings, a
one-charge coupling 818 and a load coupling 816. The PCC may be
adapted to control at least one power switch 811 by controlling the
state of the one-charge control signal 820. The power input to the
power switch 811 is coupled through the one-charge coupling 818 to
the one-charge battery(ies) 802. The power output of the power
switch 811 is presented to a rectifier 813 before being coupled
through the load coupling 816 to drive the load 804 with electrical
power 194 from the one-charge battery(ies) 802 when the power
switch 811 is closed. When the power switch 811 is open, the
rectifier 813 may prevent the wasting of electrical power in the
form of Direct Current (DC) being wasted by being propagated back
through the power switch 811 to the one-charge battery 802, that
cannot be recharged.
By way of example, the PCC 800 may include a PCC processor-unit 810
which may respond to a recharge state 806 and a load required state
812. The PCC processor-unit 810 may control the one-charge switch
814 in terms of the recharge state 806 and the load required state
812. In some situations, the one-charge battery(ies) 802 may be
connected to the load 804 in response to the load 804 being
required and insufficient recharge state. Connecting the one-charge
battery(ies) 802 to the load 804 may be achieved by asserting the
one-charge control signal 820 in response to the recharge state 806
being insufficient and the load required 812 being needed soon.
There are several implementations being disclosed and claimed for
the PCC 800 and its PCC processor-unit.
FIG. 8B shows a simplified block diagram as to how the PCC 800
and/or the PCC processor-unit may be configured to implement
various embodiments of this apparatus and its operations. The
processor-unit 810 may include at least one instance of at least
one of the following, which have each been previously discussed a
Finite State Machine (FSM) 822, a computer 824, and/or a PCC memory
828. In some implementations, the computer may be accessibly
coupled 826 to the PCC memory 826. The PCC memory 826 may contain a
PCC program system 830 that may further include program steps,
which will be further discussed regarding FIG. 8C and FIG. 8F
shortly. These program steps may instruct at least one instruction
processor within the computer 824 to implement the operations of
the PCC 800. The PCC memory 826 may contain a PCC installation
package 832. The PCC installation package may be used to configure
the FSM 822 to implement the processor-unit 810 to operate as the
PCC 800. In some embodiments, the FSM 822 may include at least one
programmable logic circuit, such as a Field Programmable Gate Array
(FPGA). In some embodiments, which may or may not be an
alternative, the PCC installation package 832 may include
instructions directing the computer 824 to create the PCC program
system 830 in the PCC memory 828.
The PCC 800 and/or the PCC processor-unit 810 may be implemented as
an integrated circuit.
In some embodiments, one or more of the computer readable memory
530, the disk drive 532, the server 534 and/or the access point 360
may contain and/or provide the PCC program system 830 and/or the
PCC installation package 832 to the processor-unit 810.
FIG. 8C shows a simplified flowchart of the PCC program system 830
of FIG. 8B. The simplest form of this program system will be
discussed first, then FIG. 8A will be revisited before completing
discussion of this flowchart. Program step 834 supports the control
820 of the one-charge switch 814 in terms of the recharge state 806
and the load required state 812. This program step may further
include Program step 836 supporting connecting the one-charge
battery(ies) 802 through the one-charge switch 814 in response to
the load required state 812 and the recharge state 806 being
insufficient.
In some implementations, the PCC processor-unit 810 may operate
and/or have access to a clock timer circuit and maintain a long
time indication sufficient to not only call out portions of a
second, but also of a day and of several months. The PCC
processor-unit 810 need only clocked at one or more thousands of
instruction cycles per second and maintain counters or variables of
16 bits or more to achieve this performance threshold. With the
approach of winter, the PCC program system 830 may be implemented
to generate and maintain the recharge state 806 and the load
required 812 without recourse to any other sensors. As a
consequence, such implementations could project the decline in the
recharge state by simply assuming that the sun was obscured or
missing from the visible sky. The load required 812 may similarly
be estimated with accuracy, particularly if the clock is shared
with other resources, such as found in a repeater 370 as shown in
FIG. 8D.
In some other implementations, the recharge state 806 and/or the
load required 812 may be sensed.
Returning to FIG. 8A, the PCC processor-unit 810 may further
respond to a Photo-Voltaic (PV) state 808. In some embodiments, the
PV state 808 may indicate that a PV cell 840, such as shown in FIG.
8D, may be capable of providing the electrical power 194 for the
load 804. In some of these situations, the PV cell(s) 840 may be
used instead to provide electrical power 194 for the load 804. As
with the recharge state 806 and/or the load required 812, the PV
state 808 may be based upon the operation of a clock timer and/or
sensed.
Returning to FIG. 8C, the PCC program system 830 may include the
following: Program step 837 that supports controlling 820 the
one-charge switch 814 in terms of the recharge state 806, the PV
state 808 and the load required 812. This program step may further
include Program step 838 that supports connecting the one-charge
battery(ies) 802 through the one-charge switch 814 in response to
the load required 812 and the recharge state 806 being insufficient
and the PV state 812 being insufficient.
Examples of the load 804 may include a radio transceiver such as
the repeater transceiver 374, a radar 912 such as discussed
starting with FIG. 9C, a processor, and/or a processor-unit as
found in various situations throughout at least this document.
Some examples of the apparatus that may include the PCC 800 are a
parking sensor 200 and/or a repeater 370. The PCC 800 may control
the electrical power 194 going to more than one load 804.
FIG. 8D shows the repeater 370 including the repeater transceiver
374 as a first load 804-1 and the repeater processor 372 as a
second load 804-2. The repeater may include one or more
photovoltaic cell(s) 840, one or more rechargeable battery(ies) 842
as well as the loads 804-1 and 804-2 coupled to the PCC 800. The
PCC 800 may operates as follows The electrical power 194 of the
photovoltaic cell(s) 840 may be directed to the rechargeable
battery (ies) 840 in response to the photovoltaic cell(s) 840 being
able to charge the rechargeable battery (ies) 840. The PCC 800 may
uncouple the rechargeable battery (ies) 840 in response to the
photovoltaic cell(s) 840 being unable to charge the rechargeable
battery (ies) 840. The PCC 800 may couple the rechargeable battery
(ies) 840 to at least one of the loads 804-1 and/or 804-2 in
response to determining the rechargeable battery (ies) 840 can
provide the sufficient electrical power 194 when it is needed. The
PCC 800 may uncouple the rechargeable battery (ies) 840 from the
load 804-1 and/or load 804-2 in response to determining that the
rechargeable battery (ies) 840 cannot provide the needed electrical
power 194. And the PCC 800 may couple the one-charge battery (ies)
802 to the load 804-1 and/or 804-2 in response to the rechargeable
battery (ies) 840 being unable to provide sufficient electrical
power 194 and in response to the load 804-1 and/or 804-2 needing
the electrical power 194.
The PCC 800 may be implemented as a circuit board, an integrated
circuit and/or as a processor instructed to act as the PCC, such as
the repeater processor 372.
In some situations, the charging of one or more rechargeable
battery (ies) 842 and the charging of one or more loads 804-1
and/or 804-2 may occur at the same time.
FIG. 9A to FIG. 9C show examples of the parking sensor 200
discussed above that may include any combination of an infrared
transceiver (possibly just its transmitter or receiver), an
ultrasonic sensor and/or a radar. Such sensors may be configured to
operate in accord with the preceding discussion. FIG. 9A shows an
example of two instances of the parking sensor 200 including
infrared transceiver components. The parking sensor 200 may be
configured to use the infrared transceiver 900 to estimate the
distance of the vehicle 12 using a triangulation approach where the
first infrared sensor transmits 902 an infrared signal that bounces
off of the vehicle 12 and is received 904 by the second infrared
sensor. Note that some parking sensors 200 may have only an
infrared transmitter 902, such as the first parking sensor 200-1,
and others an infrared receiver 904, such as the second parking
sensor 200-2. In other cases, the parking sensor 200 may include
both the infrared transmitter and the infrared receiver, which is
referred to herein as an infrared transceiver 900. FIG. 9B shows an
example of one instance of the parking sensor 200 including an
ultrasonic sensor 910 that transmits an ultrasonic signal that
bounces off of the vehicle 12 and is received by the ultrasonic
sensor 910. FIG. 9C shows an example of one instance of the parking
sensor 200 including a radar 912 that transmits a microwave signal
as an antenna output 3122 that bounces off of the vehicle 12 to
create a Radio Frequency (RF) reflection 3124 received by the radar
912.
FIG. 9D shows some details of the radar 912 implemented as possibly
a combination of a micro-radar 3100, a Zero Intermediate Frequency
(ZIF) radar 916, and/or a superheterodyne radar 916. A micro-radar
3100 may have an antenna output 3122 of less than ten milli-watts
(mW). A ZIF radar 916 may lack an Intermediate Frequency (IF)
section in both its transmitter and its receiver. A superheterodyne
radar 916 includes an IF section in at least one of its transmitter
and/or its receiver. The superheterodyne radar 916 may further be
implemented as a homodyne radar 918 that shares an oscillator
between its transmitter and receiver.
Here are some examples of the radar 912 that may be useful in a
variety of situations. Particularly when the parking sensor 200
supports a wireline communication protocol and may further possess
the opportunity to be supplied with electrical power 194 across a
landline, the radar 912 may not be a micro-radar 3100.
FIG. 10A shows a refinement of the parking sensor 200 of FIG. 9C
including the radar 912 coupled to at least one microwave antenna
920 with a transmission/reception pattern 922 as shown in FIG. 10B.
As show herein, the parking sensor 200 will be positioned at the
center of a polar coordinate grid throughout this disclosure. The
transmission/reception pattern 922 may dominate one half the plane
of transmission, which will be referred to as the half plane 924.
Dominating the half plane supports the parking sensor 200
distinguishing between vehicle 12 and the second vehicles 12-2
parked in adjacent parking spots 20. Put another way, the
transmission reception pattern 922 may be shaped to be
asymmetrically receptive in one half plane of reception as shown in
FIG. 10B, so that the radar 912 combined with the microwave antenna
920 can distinguish between a first vehicle 12 parked in a first
parking spot 20 and a second vehicle 12-2 parked in a second
parking spot 20-2.
The radar 912 may operate as the micro-radar 310. The microwave
antenna 920 may be adapted to form a single sided lobe pattern with
a focused direction used to generate the direction from the parking
sensor 200 to the vehicle 12 as part of the determination of the
parking position 130 of the vehicle 12 in the parking spot 20.
FIG. 11A and FIG. 11B show examples of implementations of the
parking sensor 200 with a wireline and a wireless network
communications interfaces, respectively. FIG. 11A shows the parking
sensor 200 including a radio antenna 926 adapted for wireless
communication and a microwave antenna 920 adapted for use with the
radar 912. FIG. 11B shows another implementation of the parking
sensor 200 including a wireline connector 928 adapted for at least
communications and the microwave antenna 920 adapted for use with
the radar 912. The wireline communications interface may further be
adapted to provide electrical power 194 to the parking sensor
200.
FIG. 11C shows an example of the microwave antenna 920 including at
least one patch antenna 934-1 and possibly a patch antenna array
932 including the patch antennas 934-1, 934-2 and/or 934-3. The
radar 912 may be fabricated immediately below the microwave antenna
920, the patch antenna 934-1 and/or the patch antenna array 932.
The radar 912 and/or the microwave antenna 920 may be fabricated as
a printed circuit 3104 and/or as an integrated circuit 3102.
FIG. 11D shows an example of the microwave antenna 920 of FIG. 11C
further including a concave reflector 936 to support shaping the
transmission/reception pattern.
FIG. 11E to FIG. 11J show examples of the microwave antenna 920
including a radiator 940 feeding a horn antenna 960 and/or a
waveguide 950 and possibly further tuned by one or more tuning bars
962 outside the horn antenna 960. FIG. 11E shows the microwave
antenna 920 including the radiator 940 coupled with the wave guide
950 to send the antenna output 3124 and receive the RF reflection
3124. FIG. 11F shows the microwave antenna 920 including the
radiator 940 coupled with the horn antenna 960 and responding to at
least one of the tuning bar(s) to send the antenna output 3124 and
receive the RF reflection 3124. FIG. 11G shows the microwave
antenna 920 including the radiator 940 coupled with the wave guide
950 creating a right angle bend and coupled with the horn antenna
960 to send the antenna output 3124 and receive the RF reflection
3124. FIG. 11H shows a refinement of the microwave antenna 920 of
FIG. 11G with the horn antenna 960 responding to at least one of
the tuning bars 962 to send the antenna output 3124 and receive the
RF reflection 3124. FIG. 11i and FIG. 11J show an implementation of
the microwave antenna 920 of FIG. 11H. In some situations the
waveguide 950 may be considered to have a nearly constant aperture
cross-section as it bends in one radial dimension. The bend in the
waveguide 950 may be about 60 degrees to 110 degrees. In some
embodiments, the bend may be about 80 degrees to 100 degrees. In
some further embodiments, the bend may be about 85 degrees to 95
degrees. The horn antenna 960 may increase in the aperture cross
section as it progresses away from the radiator 940. The horn
antenna 960 may have a depth of roughly one quarter or more of the
wavelength of the antenna output 3122. Assume for the moment that
the carrier frequency 3123 of the antenna output 3122 is about 6.36
Giga Herz (GHz). The horn antenna 960 may then have a depth of
roughly 1 centimeter (cm) to 1.5 cm.
The tuning bar(s) 926 may have a thickness of at least 2
millimeters (mm) to 1 cm. The tuning bar(s) 926 may have a height
of at least one quarter the wavelength of the antenna output 3122
to at most three halves the wavelength. As used herein, the
wavelength is about the speed of light divided by the carrier
frequency 3123 of the antenna output 3122.
The radiators 940 may include versions of a single pole, a dipole,
a patch antenna and/or a patch antenna array.
FIG. 12A to FIG. 12C show an example of the parking sensor 200
including two microwave antennas that may be configured to
separately detect the first vehicle 12 in the first parking spot 20
and the second vehicle 12-2 in the second parking spot 20-2. FIG.
12A shows a simplified mechanical drawing of the parking sensor 200
with the first microwave antenna 920 and the second microwave
antenna 920-2 positioned on either side of the radio antenna 926.
This antenna assembly is attached to the sensor package 930 and
possibly a battery store. The microwave antenna 920 is adapted to
generate the antenna output 3122 in a first direction indicated by
an arrow and to receive the RF reflection 3124 in that first
direction. The second microwave antenna 920-2 may be adapted to
generate the antenna output in a second, nearly opposite direction,
and to receive the RF reflection 3124 in the second direction. FIG.
12B shows a simplified block diagram of the parking sensor 200
showing a microwave switch 970 controlled by a sensor processor 300
to operate the coupling of the radar 912 with one of the two
microwave antennas 920 and 920-2. FIG. 12C shows the parking sensor
200 detecting the first vehicle 12 in the first parking spot 20
using the first microwave antenna 920 coupled through the microwave
switch 970 to the radar 912. FIG. 12D shows the parking sensor 200
detecting the second vehicle 12-2 in the second parking spot 20-2
by using the second microwave antenna 920-2 coupled through the
microwave switch 970 to the radar 912.
One skilled in the art will recognize that implementations of the
parking sensor 200 with more than two microwave antennas, for
instance, four microwave antennas. FIG. 13A to FIG. 13D show the
use of such a sensor adaptation that can determine a vehicle 12
parking in one of four parking spots 20.
The prior art includes a discussion that radar transmission signals
in multi-GigaHertz (GHz) bands are unaffected by changing weather
conditions. While this is true, the prior art overlooks some issues
that the inventor has had to cope with. The inventor has found each
of the following issues to seriously affect at least some
installations of micro-radar: Different manufacturing runs may
alter the operating characteristics of the micro-radar, even in a
laboratory setting. Varying temperature/weather conditions may
alter the operating characteristics. Varying ground conditions for
a micro-radar embedded in the ground may alter the operating
characteristics. The micro-radar components may also drift over
time even when there are little or no changes in the weather or
ground conditions. The component drift may also alter the operating
characteristics. Often, there may be variations in the noise in the
Intermediate Frequency (IF) signal that can compromise the
detection and/or distance estimate. Often, there is a need to
operate the micro-radar in a manner that minimizes power
consumption. For example, in some wireless sensor nodes, there is a
very limited amount of power that can be generated and/or stored by
the wireless sensor node, requiring that a micro-radar use power in
a frugal manner.
These operating characteristics of the micro-radar may include
changes in the IF frequency and/or noise of the micro-radar and/or
changes in the timing delays of the receiver. Changes in either or
both of these characteristics can adversely affect a sensor's
ability estimate the travel time of the radar pulse and from that
render the distance estimate to an object less accurate.
The application discloses and claims several embodiments, a
superheterodyne radar, possibly the homodyne radar, sensor nodes
adapted to interact with the superheterodyne radar, processors
responding to the superheterodyne radar, as well as systems and
components supporting communications between the superheterodyne
radar and the processors. The processors and systems may further
support traffic analysis and management of moving and/or stationary
vehicles 12. The vehicles 12 may include sections of non-magnetic
materials such as aluminum, wood and/or plastics that tend to
create false readings for magnetic sensors. The processors and
systems may also support measurement and/or management of
production processes such as chemical production, device
fabrication and container filling of various items such as liquids,
grains and/or saw dust.
The superheterodyne radar 916 and/or the homodyne radar 918 may be
adapted to operate in response to at least one output of a Digital
to Analog Converter (DAC) and sometimes preferably two DAC
outputs.
The DAC output may be used to generate an analog sum including an
exponentially changing signal and the output of the DAC. Here are
two examples of the response of the superheterodyne radar, possibly
the homodyne radar, to distinct analog sums, either or both of
which may be incorporated into the superheterodyne radar, possibly
the homodyne radar, and/or its operations: First, the
superheterodyne radar and/or the homodyne radar may operate in
response to a first analog sum of a first DAC output, an
exponentially changing signal, and a clock pulse. The response may
include generating a receiver mixing signal that is asserted at a
succession of time delays that are a function of the first analog
sum. Second, the superheterodyne radar and/or the homodyne radar
may be operated based upon a second analog sum of a second
exponentially changing signal and a second DAC output to control
the Intermediate Frequency of the the down converted RF signal.
This second sum may control a duty cycle of a pulse generating
oscillator output without changing its frequency. The duty cycle
may be measured as the high time divided by the period of the
oscillator output.
The superheterodyne radar and/or the homodyne radar may include a
RF transceiver/mixer RFTM used to generate carrier signal for the
antenna output and to generate the received IF signal.
The superheterodyne radar and/or the homodyne radar may be operated
through the control of the first and/or second DAC outputs. Some
operations that may be supported include any combination of the
following: Controlling both the first and second DAC outputs to
advance or retard the sweep delay relative to the distance to an
object. Setting the second DAC output to generate the IF signal as
a noise reading. And calibrating the first DAC output, and possibly
the second DAC output, to establish the IF frequency.
The apparatus may further include a wireless sensor node and/or a
wireline sensor node and/or a processor and/or an access point
and/or a server. The wireless sensor node may include a first
instance of the superheterodyne radar and/or the homodyne radar and
a radio transceiver configured to send a report regarding the sweep
delay for the object, when the IF signal has a peak amplitude
corresponding to the received RF reflection from the object. The
wireline sensor node may be configured to operate a second instance
of the superheterodyne radar and/or the homodyne radar and
including a wireline interface configured to send the report
regarding the sweep delay for the object. The processor may be
configured to receive the report and configured to respond to the
report by generating an estimate of the distance of the object from
the superheterodyne radar and/or the homodyne radar. The access
point may be configured to wirelessly communicate with the
superheterodyne radar and/or the homodyne radar via the radio
transceiver to send a version the report to the processor. And the
server may be configured to communicate the version of the report
from the superheterodyne radar and/or the homodyne radar to the
processor.
The wireless sensor node and/or the wireline sensor node may
further include a sensor processor configured to control the
superheterodyne radar and/or the homodyne radar by at least control
of the first DAC output and the second DAC output.
At least one of the sensor processor, the access point, the server
and/or the processor includes at least one instance of at least one
of a finite state machine and a computer accessibly coupled to a
memory containing a program system comprised of program steps
configured to instruct the computer.
Various implementations of the program system may include at least
one of the program steps of: Operating the superheterodyne radar
and/or the homodyne radar based upon control of the first DAC
output and/or the second DAC output. Receiving the IF signal to
generate an ADC reading and/or an estimate of the sweep delay for
the object. Estimating the distance of the object based upon the
estimated sweep delay. Generating the report based upon the ADC
reading and/or the sweep delay. Responding to the report by sending
the version of the report to the processor. Second responding to
the report and/or the version to estimate the distance of the
object from the superheterodyne radar and/or the homodyne radar.
Third responding to the report and/or the version to generate the
size of the object. And/or fourth responding to the distance of the
object from the superheterodyne radar and/or the homodyne radar by
updating at least one of a traffic monitoring system, a traffic
control system, a parking management system, and/or a production
management system.
The apparatus may further include at least one of the traffic
monitoring system, the traffic control system, the parking
management system, and/or the production management system, any of
which may include At least one communicative coupling to at least
one of the micro-radar, the wireless sensor node, the wireline
sensor node, the processor, the access point and/or the server. The
communicative coupling(s) may support communication across at least
one of a wireline physical transport and/or a wireless physical
transport.
FIG. 14 shows a simplified block diagram of an example of a
wireless sensor node 3300 and/or a wireline sensor node 3310 that
may include a sensor processor 3000 configured to operate a
micro-radar 3100, a superheterodyne radar 918 and/or a homodyne
radar 918 based upon a first DAC output 3110 and second DAC output
3112. An object 3020 may be situated at a distance 3022, for
example a distance T0, from an antenna 3120 interacting with the
micro-radar 3100. In many situations, the antenna and the
micro-radar may be considered as located at one location, but in
other situations, there may be some distance between them. To
simplify this discussion, only the distance 3022 from the antenna
will be discussed. The object 3020 may reflect the antenna output
3122 to generate a RF reflection 3124. The micro-radar 3100, the
superheterodyne radar 916 and/or the homodyne radar 918 may be
adapted to generate a received RF reflection 3152 from the RF
reflection 3124. The micro-radar 3100, the superheterodyne radar
916 and/or the homodyne radar 918 may use a timing generator 3150
adapted to respond to the two DAC outputs 3110 and 3112 to generate
a transmit signal 3210 and a reception signal 3220 that stimulate a
Radio Frequency (RF) transceiver/mixer (RFTM) 3300 to generate the
antenna output 3122 and to down convert an Intermediate Frequency
(IF) signal 3160 based upon and proportional to the received RF
reflection 3152.
Consider the micro-radar 3100, the superheterodyne radar 916 and/or
the homodyne radar 918 response to the first DAC output 3110 and to
the second DAC output 3112 over the clock period 3117 of a sweep
clock 3116. The sweep clock 3116 may be generated by a separate
clock generator 3030. In other implementations, the micro-radar
3100, the superheterodyne radar 916, the homodyne radar 918 and/or
the sensor processor 3000 may include the clock generator. The
timing generator 3150 may respond to the first DAC output 3110 by
generating a transmit signal 3210 over the clock period 3117 of
sweep clock 3116 as shown in FIG. 15A, which will be discussed
shortly. The timing generator 3150 may respond to the second DAC
output 3112 by generating a reception signal 3220 with a time delay
3300 from the transmit signal over the sweep clock 3116 period
3117, also shown in FIG. 15A. A first one-shot multi-vibrator 3060
may respond to the transmit signal 3210 by generating the transmit
pulse 3212. A second one-shot multi-vibrator 3062 may respond to
the reception signal 3220 by generating the reception pulse 3222.
The RFTM 3300 may respond to the transmit pulse 3210 by generating
a transmitted Radio Frequency (RF) burst 3132 for delivery to the
antenna 3120 to generate the antenna output 3122. The RFTM 330 may
mix a received RF reflection 3152 with the transmit RF burst 3132,
in response to the reception pulse 3220, to generate the IF signal
3160 with a peak amplitude 3164 at a sweep delay Tm for a distance
T0 of the object 3020 from the antenna 3120. The frequency 3160 of
the IF signal 3160 is preferably about one over the compression
ratio multiplied by the carrier frequency 3123 of the antenna
output 3122, where the compression ratio is about one million.
A pulse generator 3400 may be used to respond to the transmit
signal 3210 to generate the transmit pulse 3212 and to respond to
the reception signal 3220 to generate the reception pulse 3222. The
transmit signal may further stimulate a first one shot
multi-vibrator 3060 to at least partly generate the transmit pulse.
The reception signal may further stimulate a second one-short
multi-vibrator 3060-2 to at least partly generate the reception
pulse. Note that in some implementations, the reception pulse may
include the transmit pulse occurring before at a time delay 3300
before it. The time delay will be shown in FIG. 2A. FIG. 2A will
show the reception pulse not including the transmit pulse.
Before discussing the timing relationships in FIG. 15A and FIG.
15B, there are two questions to answer: Where does the compression
ratio show up in this apparatus? And what is the relationship of
the duty cycle 3218 of the transmit signal 3210 to compression
ratio and the frequency 3162 of the IF signal 3160?
First, here is how the compression ratio shows up. The carrier
frequency 3123 of the antenna output 3122 is in the GigaHertz (GHz)
range. For example, in the inventor's products, which include
wireless sensor nodes 3310, the carrier frequency is about 6.3 GHz.
The return times for the antenna output 3122 to travel the distance
T0 of 6 feet to the object 3020 and return are as the RF reflection
are about 12 nanoseconds. But the system clock for the sensor
processor 3000 is about 32 KHz. This clock frequency is set low to
conserve on power stored in the wireless sensor node 3310. The
sensor processor cannot directly detect the reception time Tm of
the RF reflection 3124 without consuming a lot more power than can
be afforded. There are RFTM 3212 and similar micro-radar 3100
circuits that held a promise of meeting these needs, in that the
frequency 3162 of the IF signal 3160 is one millionth of the
carrier frequency 3123, making the IF frequency about 6.3 KHz,
which is within the operating frequency of the sensor processor
3000. Because of the compression ratio, the frequency 3162 of the
IF signal 3160 frequency 3162 is small enough that sensing it can
be done efficiently enough for a wireless sensor node 3300.
Here is where the duty cycle and its relationship to the
compression ratio and the frequency 3162 of the IF signal 3160
shows up: The inventor obtained some samples of micro-radars, and
they worked. However, when he made then some that had the same
schematic and they did not work. It turned out the there were
manufacturing variations in the components that changed the
compression ratio and consequently, the frequency 3162. After much
experimentation, he found that by adding DAC outputs 3110 and 3112
to generate the transmit signal 3210 and the receive signal 3220,
and measuring the duty cycle of the transmit signal, he could
control the compression ratio at the same time he controlled the
duty cycle. This also allowed a program to be executed on the
sensor processor 3000 that could change the first DAC output 3110
until the duty cycle 3218 was within a factional range of the clock
period 3117 of the sweep clock 3116. For instance, he found that if
the ratio of the duty cycle to the clock period was 50%, the
frequency 3162 of the IF signal 3160 was about 10 KHz, whereas if
the ratio was about 70%, the frequency was about 6.3 KHz. There is
no immediate theory that seems to account for this phenomena, but
experimentally it has been found to be true. Further, field testing
of the wireless sensor nodes 3310 has revealed that the compression
ratio and therefore the frequency 3162 of the IF signal 3160 of
these micro-radars 3100 are also sensitive to fluctuations in
temperature 3125. However, it was again discovered that if the
first DAC output 3110 was adjusted until the duty cycle estimate
3012 was again adjusted until it was in the vicinity of 70%, the
frequency 3162 of the IF signal 3160 was again in the range of 6.3
KHz.
Before continuing the discussion of FIG. 14, the timing
relationships involved with this micro-radar will be shown and
discussed in FIG. 15A to FIG. 15C.
FIG. 15A shows a timing diagram of the relationship between the
sweep clock 3116, the transmit signal 3210 and the reception signal
3220 as generated by the timing generator 3150 and used by the RFTM
3300, including the time delay 3300 between the signals and/or the
pulses, the pulse widths and duty cycle 3218. The transmit signal
3210 and the reception signal 3220 may be generated once in every
cycle of the sweep clock 3116 by the timing generator 3150. The
sweep clock has a clock period 3117, which in some situations is
about 6.3 MHz. The duty cycle 3218 of the transmit signal 3210 is
the time in the clock period 3117 in which the signal is high,
which is often referred to as logic `1`. The transmit pulse 3212 is
initiated in response to a first edge 3214 of the transmit signal
3210. Since the micro-radar 3100 circuitry is so much faster than
the sensor processor 300 and the wireless sensor node 3300 in
general, there are no delays shown between the first edge 3214 and
the transmit pulse 3212 starting. The reception pulse 3222 is
initiated in response to a second edge 3224 of the reception signal
3220, again shown with no delays. However, there is a time delay
3300 between the first edge 3214 and the second edge 3224, which
leads to essentially the same delay between the transmit pulse 3212
and the reception pulse 3222. The transmit pulse width 3304 is
shown as the active high width of the transmit pulse 3210. The
reception pulse width 3302 is shown as the active high width of the
reception pulse 3220. Both the transmit pulse with 3304 and the
reception pulse width 3302 are about the same, and in some
situations may be about 4 ns.
FIG. 15B shows a timing diagram sweep of the time delay 3300 from a
short delay 3330 to a long delay 3332 over a time interval 3350, as
well as the IF signal 3160 over the time interval with a peak
amplitude 3164 at a sweep delay Tm corresponding to the distance T0
of the object 3020 from the antenna 3120 as shown in FIG. 14. The
time interval may see the sweep start at the short delay and
progress to the long delay as is shown. In other implementations,
the time interval may see the opposite, that the sweep starts at
the long delay progresses to the short delay.
Since the pulse widths 3302 and 3304 are essentially the same, for
example, both about 4 ns, avoiding a collision between sending the
antenna output 3122 and receiving the RF reflection 3124, can be
served by setting the short delay 3330 to 4 ns. Setting the long
delay 3332 to 20 ns after the short delay leads to setting the long
delay to 24 ns, allowing for seep delays Tm that corresponding to
traversing to and from the object at a distance roughly 10 feet,
which is sufficient for many applications of the micro-radar
3100.
The IF signal 3160 is shown with a peak labeled a big bang 3352
before the start of the time interval 3350. The big bang is an
occurrence where the sweep start 3038 is initiated earlier than
shown in this Figure. In such a situation, the transmit RF burst
3132 and the reception pulse 3222 overlap in time, causing a false
peak, irrespective of the received RF reflection 3152. In some
situations, it may be preferred to operate the micro-radar 3100 so
that the sweep start occurs after the big bang, not only saving
power but also removing the need to remove the false peak from the
detection of the sweep delay Tm.
The sensor processor 3000 shown in FIG. 14 may use an Analog to
Digital Converter (ADC) 3020 less than 20 thousand times a second
and yet determine the distance T0 very accurately, while being able
to calibrate itself to account for variations in manufacturing,
temperature 3125 and other ambient conditions.
The IF signal 3160 is also shown in FIG. 2B with a persisting
trough occurring after the time interval 3350. This trough is
labeled background noise 3354. By operating the micro-radar 3100
after the time interval, the IF signal may be sampled to create one
or more ADC readings 3016 that may be used to generate a background
noise estimate 3013 shown in FIG. 14. While the background noise
has been shown as a persisting trough, it may take any of a wide
variation in shapes and be encompassed in the scope of the claims.
Background noise is noisy, but tends to be relatively small
compared to the the IF signal during the time interval, when
received RF reflections 3152 increase the amplitude of the IF
signal as shown in FIG. 2B.
Detecting the object 3020 may also involve using a detect threshold
3011, which will be discussed later. The sensor processor 3000 may
include the detect threshold, which may be generated from the
background noise estimate 3013, shown first in FIG. 14 and further
shown in FIG. 2B.
The micro-radar 3100 and/or the RFTM 3200 may be implemented as at
least part of an integrated circuit 3102 and/or a printed circuit
3104. Through the use of the first DAC output 3110 and the second
DAC output 3112, initial and later calibration of the micro-radar
3100, the integrated circuit 3102 and/or the printed circuit 3104
may be cost effectively performed, thereby minimizing production
test costs and improving reliability in varying field
conditions.
The micro-radar 3100, the superheterodyne radar 916 and/or the
homodyne radar 918 may be operated by the sensor processor 3000
through interactions with the DAC and an Analog to Digital
Converter (ADC) 3020. The setting of the DAC outputs 3110 and 3112
have been described to some extent. A duty cycle estimator 3170 may
respond to the transmit signal 3210 to generate a duty cycle signal
3172 presented to an Analog to Digital Converter (ADC) to generate
an ADC reading used to calculate a duty cycle estimate 3012. The IF
signal 3160 may be sampled by the ADC 3020 to create a possibly
different ADC reading 3016 used to generate the IF sample 3014 at
an estimated sweep delay Tm.
FIG. 14 shows one DAC 3010 generating both the first DAC output
3010 and the second DAC output 3112 and being coupled 3002 to the
sensor processor 3000. Various implementations of the DAC 3010 may
be used to generate the first DAC output 3110 and/or the second DAC
output 3112. These implementations of the DAC 3010 do not have to
be the same, may differ in resolution and sampling rate. However,
the discussion will proceed to illustrate one DAC generating both
the first and second DAC outputs. This is not intended to limit the
scope of the claims. It is done for the sake of simplifying the
discussion. Also, the resolution of the DAC outputs 3110 and/or
3112 may be at least 10 bits, and in some situations may be
preferred to be more than 10 bits. The coupling 3002 between the
sensor processor 3000 and the DAC 3010 today is preferably a
wireline coupling, frequently involving one or more electrically
conductive materials. However other implementations may be
preferred. For example, the coupling may also implement an optical
coupling which might not be electrically conductive.
FIG. 14 also shows the sensor processor 3000 second coupled 3004 to
an Analog to Digital Converter (ADC) 3020. The sensor processor
and/or the wireless sensor node 3300 and/or the wireline sensor
node 3310 may be adapted and/or configured to use the ADC 3120 in
one or more of the following ways: The ADC 3020 may respond to the
duty cycle signal 3212 and the interactions of the sensor processor
3000 through the second coupling 3004 to generate a duty cycle
estimate 3012 in the sensor processor, and/or The ADC 3020 respond
to the IF signal 3160 and the interactions of the sensor processor
3000 through the second coupling 3004 to generate an IF sample 3014
in the sensor processor. Various implementations of the ADC 3020
may be used to generate the duty cycle estimate 3012 and/or the IF
sample 3014. These implementations of the ADC 3020 do not have to
be the same, may differ in resolution and sampling rate. However,
the discussion will proceed to illustrate one ADC generating both
the duty cycle estimate 3012 and the IF sample 3014. This is not
intended to limit the scope of the claims. It is done for the sake
of simplifying the discussion. Also, the resolution of the ADC 3020
may be at least 10 bits, and in some situations may be preferred to
be more than 10 bits. The second coupling 3004 between the sensor
processor 3000 and the ADC 3020 today is preferably a wireline
coupling, frequently involving one or more electrically conductive
materials. However other implementations may be preferred. For
example, the second coupling may also implement an optical coupling
which might not be electrically conductive. The interactions across
the second coupling 3004 may include a selection of an analog input
port and a strobing of the ADC 3020 to provide data to be used as
the duty cycle estimate 3012 and/or the IF sample 3014.
The micro-radar 3100, the superheterodyne radar 916 and/or the
homodyne radar 918 may include a first ADC coupling 3106 of the IF
signal 3160 to the ADC 3160, and/or a second ADC coupling 3108 of
the duty cycle signal 3212 to the ADC 3160.
In some embodiments, the sensor processor 3000 may include the DAC
3010 and/or include the ADC 3020. Whereas in other embodiments, the
sensor processor, the DAC and the ADC may be separate components
fastened to a printed circuit 3104, possibly containing all or part
of the micro-radar 3100, and the first coupling 3002 and the second
coupling 3004 may be electrical traces on and/or through the
printed circuit.
FIG. 16 shows some details the micro-radar 3100, the
superheterodyne radar 916 and/or the homodyne radar 918, in
particular the timing generator 3150 of FIG. 14, including a
transmit control generator 3250 responding to the first DAC output
3110 and a reception control generator 3260 responding to the
second DAC output 3112. The transmit control generator 3250 may
include a first analog sum 3256 of a first exponentially changing
signal 3252 and the first DAC output 3110 triggering a first sharp
threshold device 3258 to generate the transmit signal 3210 with a
duty cycle 3218 as shown in FIG. 2A. The transmit signal may
stimulate the duty cycle estimator 3170 to generate the duty cycle
signal 3172 as shown in FIG. 14. Note that the first analog sum may
be generated by a first analog sum circuit 3256. The reception
control generator 3260 may includes a second analog sum 3266 of the
second DAC output 3112, a second exponentially changing signal 3262
and the sweep clock signal 3116 triggering a second sharp threshold
device 3268 to generate the reception signal 3220. The second
analog sum may be generated by a second analog sum circuit 3266.
The first and second analog sum circuits 3254 and 3264 may be
implemented in a wide variety of ways, including through the use of
differential amplifiers and/or weighted resistor networks designed
based upon Ohm's Law to generate the analog sum 3256 and/or 3266.
The first exponentially changing signal 3252 is used to generate
the transmit signal 3210, and will tend to need a fast time of
change, possibly changing from a saturation to depleted state in a
few nanoseconds. The second exponentially changing signal 3262 is
used to generate the time delay 3300 sweep from a short delay 3330
to a long delay 3332 over the time interval 3350, which may be on
the order of 20 ms. Circuitry to generate the first exponentially
changing signal 3252 and/or the second exponentially changing
signal 2166 may be implemented based upon capacitor charging and/or
discharging across a resistor, which may be further implemented
with various components of one or more transistors acting as the
capacitor and/or the resistor. In some embodiments, the
exponentially changing signals 3252 and/or 3262 may be generated
through piecewise linear behavior of threshold switching
components. Such signals may not change in an exactly exponential
fashion, but will display a distinctive change in the rate of
change which will be monotonically increasing or monotonically
decreasing within one sweep clock 3116 period 3117. The first
exponentially changing signal 3252 may have an RC delay of 20 ns.
The second exponentially changing signal 3262 may have an RC decay
of 20 ms. The delay sweep shown in FIG. 2B may be controlled by a
signal set by the sensor processor 3000 that may short the
capacitor that generates the second exponentially changing
signal.
The transmit pulse 3212 use only the high speed RC signal and the
reception pulse 3222 may use both the reception signal 3220 and the
transmit signal 32210.
FIG. 17 shows the first sharp threshold device 3258 and/or the
second sharp threshold device 3268 may include at least one
instance of a logic gate 3270, a comparator 3280 and/or a level
shifter 3282. The logic gate 3272 which may be implemented as an
inverter 3272, a NAND gate 3274, a NOR gate 3276, an AND gate 3278,
and/or an OR gate 3279. In situations where the logic gate has more
than one input, the analog sum 3256 or 3266 may be supplied to one
or more of the inputs. Any remaining inputs may be tied to logic 1
or 0 as needed.
The simplicity of using basic power logic gates 3270 instead of
more power consuming comparators 3280 is very desirable but adds to
the need to calibrate out the part to part voltage threshold
differences found in these gates. Threshold variations may cause
two major issues in the design: the IF signal 3160 frequency 3162
may vary based on the part of the RC curve that is used as the
switching point, and the time delay 3300 of the transmit pulse 3212
versus the reception pulse 3222 may create uncertainty in the
detection distance t0 versus sweep delay Tm relationship.
To address these situations, a method of calibrating the
micro-radar 3100 that can adjust for both of these uncertainties
and compensate them over temperature 3125 without a lot of power
consumption or specially calibrated parts was developed. This
method will be described later in FIG. 23 in terms of a program
system 3500 that may instruct a computer 3852.
FIG. 18 shows an example of the RFTM 3300 of FIG. 14 based upon the
circuitry of U.S. Pat. No. 6,414,627 (hereafter referred to as the
'627 patent). In this example, the carrier frequency 3123 of
antenna output 3122 is 24 GHz. A single antenna 3120 is used as
shown in FIG. 14. The RFTM emits 24 GHz RF sinewave packets and
samples echoes with strobed timing such that the illusion of wave
propagation at the speed of sound is observed, thereby forming an
ultrasound mimicking radar (UMR). A 12 GHz frequency-doubled
transmit oscillator in the RFTM is pulsed by the transmit pulse
3212 a first time to transmit a 24 GHz harmonic burst as the
transmit RF burst 3132 and pulsed by the reception pulse 3222 a
second time to produce a 12 GHz local oscillator burst for a
sub-harmonically pumped, coherently integrating sample-hold
receiver (homodyne operation). The time between the first and
second oscillator bursts is swept as shown in FIG. 2B to form an
expanded-time replica of echo bursts at the receiver output as the
IF signal 3160.
A random phase RF marker pulse may be interleaved with the coherent
phase transmitted RF antenna output 3122 to aid in spectrum
assessment of the micro-radar's 3100 nearly undetectable emissions.
The low-cost micro-radar 3100 can be used for automotive backup and
collision warning, precision radar rangefinding for fluid level
sensing and robotics, precision radiolocation, wideband
communications, and time-resolved holographic imaging.
The RFTM 3300 may be implemented as a transmit oscillator and as a
swept-in-time pulsed receive local oscillator. This dual function
use of one oscillator eliminates the need for two microwave
oscillators and facilitates operation with only one antenna for
both transmit and receive functions. Further, it assures optimal
operation since there are no longer two oscillators that can go out
of tune with each other (in a two oscillator system, both
oscillators must be tuned to the same frequency).
The transmit RF burst 3132 may be short, perhaps on the order of a
few nanoseconds and sinusoidal, is transmitted to as the antenna
output 3122 and reflected as the RF reflection 3124 from the object
3020. Shortly after transmission, the same RF oscillator used to
generate the transmit pulse is re-triggered to produce a local
oscillator pulse (homodyne operation) as the reception pulse, which
gates a sample-hold circuit in to produce a voltage sample. This
process may be repeated at a several megaHertz rate as controlled
by the sweep clock 3116. With each successive repetition, another
sample may be taken and integrated with the previous sample to
reduce the noise level. Also, each successive local oscillator
pulse is delayed slightly from the previous pulse such that after
about the time interval 3350, the successive delay increments add
up to a complete sweep or scan from the short delay 3330 to the
long delay 3332, for example, of perhaps 100-nanoseconds or about
15 meters in range. After each scan, the local oscillator delay is
reset to a minimum and the next scan cycle begins.
The micro-radar 3100 produces a sampled voltage waveform on a
millisecond scale that is a near replica of the RF waveform on a
nanosecond scale. This equivalent time effect is effectively a
dimensionless time expansion factor. If the compression ratio is
set to 1-million, 24 GHz sine waves are output from the micro-radar
as 24 kHz sine waves. Accordingly, the radar output can be made to
appear like an ultrasonic ranging system. In addition to having the
same frequency, e.g., 24 kHz, a 24 GHz radar actually has the same
wavelength as a 24 kHz ultrasonic system. In addition, the range
vs. round-trip time is the same (in equivalent time for the radar,
of course).
The emission spectrum from the RFTM 3300 is very broad and often
implemented as an Ultra Wide-Band (UWB) compliant signal generator.
Sometimes, a narrowband, incoherent RF marker pulse may interleaved
with the short coherent RF pulses used for ranging to produce a
very visible spectrum with an identifiable peak, i.e., carrier
frequency 3123. However, the marker pulse may create spurious
echoes. Accordingly, the marker pulse may be randomized in phase so
its echoes average to zero in the RFTM. At the same time, the
desired ranging pulses as the antenna output 3122 and the RF
reflection 3124 phase-coherently integrating from pulse to pulse
into a clean IF signal 3160.
FIG. 18 shows some details of the micro-radar 3100, the
superheterodyne radar 916 and/or the homodyne radar 918, and the
RFTM 3300 of FIG. 14 adapted to operate as in the '627 patent. A
harmonic oscillator 3312 receives the transmit pulse 3212 from the
transmit signal 3210 via pulse generator 3400 and produces RF burst
pulses as the transmit RF burst at the antenna 3120 as shown in
FIG. 14.
In some implementations the transmit signal 3210 may be a 1-10 MHz
square wave that is passed through pulse generator to form about 1
ns wide transmit pulses 3212 with rise and fall times on the order
of 100 picoseconds (ps). The transmit pulse 3212 and the reception
pulse 3222 may be clock pulses with very fast rise and fall times.
The transmit pulse 3212 and pulse generator 3400 may together be
viewed as a clock signal generator. These short pulses bias-on the
harmonic oscillator 3312, which is designed to start and stop
oscillating very rapidly as a function of applied bias. The
oscillations of the transmit pulses 3212 are phase coherent with
the drive pulses, the phase of the RF sinusoids of the transmit RF
burst 3132 relative to the drive pulse remains constant, i.e.,
coherent, each time the harmonic oscillator 3312 is started--there
is little clock-to-RF jitter. However, as will be discussed below
with reference to the marker generator 3450, separate marker pulses
M may have a random phase relative to the clock.
A high degree of phase coherence for the transmit pulse 3212 may be
obtained with a very fast rise time transmit signal 3210 that
shock-excites the harmonic oscillator 3312 into oscillation.
Accordingly, the pulse generator 3400 may have transition times of
about 100 ps to ensure coherent harmonic oscillator startup.
The harmonic oscillator 3312 may operate at a fundamental frequency
of 12.05 GHz with a second harmonic at 24.1 GHz. A frequency of
24.1 GHz or thereabouts may be preferred since commercial and
consumer devices such as radar rangefinders can operate in the
24.0-24.25 GHz band without a license. The transmitted RF bursts
3132 may be typically 12 cycles long at a carrier frequency 3123 of
24.1 GHz
The reception signal 3220 may be a 1-10 MHz square wave passed
through pulse generator 3400 to form the reception pulse 3222 as
about 1 ns wide pulses with rise and fall times below 100 ps. These
short pulses bias-on the harmonic oscillator 3312 to generate the
reception pulse 3222 in a similar fashion to the transmit pulses
3212 to form the reception pulses as 0.5 ns wide gate pulses. The
reception pulses 3222 gate the harmonic sampler 3330 at typical
frequency of 12 GHz to sample the received RF reflection 3152.
The harmonic sampler 30 develops a detected signal 3332,
representing the coherent integration of multiple gatings of
sampler 30, which is amplified by a low frequency amplifier 3331
and filtered in bandpass filter 3332 to produce the IF signal 3160
signal.
The micro-radar 3100, the superheterodyne radar 916 and/or the
homodyne radar 918 may include a marker generator 3450. The marker
generator may be triggered by pulses from the pulse generator 3400
to form marker pulses 3452 which are much wider than the transmit
pulse 3212 or the reception pulse 3222. Due to the width of the
marker pulses 3452, the radiated spectrum becomes relatively
narrow, since the emission spectrum is roughly related by 1/PW,
where PW is the width of the emitted pulses. One purpose of the
narrow marker pulse spectrum is to aid in identifying the RF
carrier frequency 3123 and spectral width of the transmitted pulses
3212 and/or the transmit RF burst 3132.
Note that in some implementations, the amplifier 3331 and the
bandpass filter 3332 may be implemented by a single component. Such
a component may be a fixed gain (possibly about 45 dB) 6 pole
bandpass amplifier centered at 6.5 kHz with a bandwidth of
approximately 24 kHz. In other implementations, fewer gain stages
may be used with the filtering reduced to say 4 poles.
FIG. 19 shows some examples of the object 3020 as at least one of a
person 3021, a bicycle 3022, a motorcycle 3023, an automobile 3029,
a truck 3024, a bus 3025, a trailer 3026 and/or an aircraft
3027.
FIG. 20 shows some examples of the object 3020 as a surface of a
filling 3028 of a chamber 3029, where the filling may be a liquid
and/or granules such as grain, powders and/or sand. The chamber may
be used for storage and/or mixing of components which may be
considered as the filling in some implementations.
FIG. 21 shows some other apparatus embodiments that involve the
micro-radar 3100, the superheterodyne radar 916 and/or the homodyne
radar 918 of FIG. 14, including but not limited to, the wireless
sensor node 3600, the wireline sensor node 3650, each of which may
send reports 3620 and/or 3620-2 regarding the sweep delay Tm
sampled by their respective the micro-radar 3100, the
superheterodyne radar 916 and/or the homodyne radar 918, to an
access point 3700 and/or a server 3750. A processor 3800, which may
be separate from, or included in the access point and/or the server
may respond to one or both reports to generate an estimated
distance approximating the distance T0 of the relevant microwave
antenna 920 or 3120-2 from the object 3020, in this example, a
truck 3024.
The wireless sensor node 3600 may include a radio 3630 coupled to a
radio antenna 926 to wirelessly communicate 3642 the report 3620 to
the access point 3700. As shown in this Figure, the processor 3800
may be included in the access point and configured to use the
report 3620 to create the sweep delay Tm, local to the access point
and/or the processor. The processor may further be configured to
respond to the sweep delay Tm by generating an estimated T0
distance of the microwave antenna to the object 3020. The radio
antenna 926 and the microwave antenna 920 may be located near the
top of the wireless sensor node 3600, which may be embedded in the
pavement 3008.
The wireline sensor node 3650 may not include the second
micro-radar 3100-2, second superheterodyne radar 916-2 and/or
second homohdyne radar 918-2, but may communicate with it in a
fashion similar to that described with regards FIG. 14. The second
antenna 3120-2 may or may not be located close to the second
micro-radar 3100-2, second superheterodyne radar 916-2 and/or
second homohdyne radar 918-2. The wireline sensor node may operate
the second micro-radar 3100-2, second superheterodyne radar 916-2
and/or second homohdyne radar 918-2 to generate a second sweep
delay Tm corresponding to a second distance T0 of the second
antenna from the object 3020. The wireline sensor node may wireline
communicate 3652 with the server 3750 and/or the access point 3700.
The processor 3800 may be included in the server and may be
configured to respond to reception of the second report by
generating the second sweep delay Tm. The processor may further
respond by generating a second distance estimate T02 based upon the
second sweep delay Tm.
FIG. 22 shows some details of at least one of the sensor processor
3000 and/or the processor 3800 may be individually and/or
collectively may be implemented as one or more instances of a
processor-unit 3820 that may include a finite state machine 3850, a
computer 3852 coupled 3856 to a memory 3854 containing a program
system 2300, an inferential engine 3858 and/or a neural network
3860. The apparatus may further include examples of a delivery
mechanism 3830, which may include a computer readable memory 3822,
a disk drive 3824 and/or a server 3826, each configured to deliver
3828 the second program system 2300 and/or an installation package
3809 to the processor-unit 3820 to implement at least part of the
disclosed method and/or third apparatus. These delivery mechanisms
3830 may be controlled by an entity 3820 directing and/or
benefiting from the delivery 3828 to the processor-unit 3820,
irrespective of where the server 3826 may be located, or the
computer readable memory 3822 or disk drive 3824 was written. As
used herein, the Finite State Machine (FSM) 3850 receives at least
one input signal, maintains at least one state and generates at
least one output signal based upon the value of at least one of the
input signals and/or at least one of the states. As used herein,
the computer 3852 includes at least one instruction processor and
at least one data processor with each of the data processors
instructed by at least one of the instruction processors. At least
one of the instruction processors responds to the program steps of
the second program system 2300 residing in the memory 3854. As used
herein, the Inferential Engine 3858 includes at least one
inferential rule and maintains at least one fact based upon at
least one inference derived from at least one of the inference
rules and factual stimulus and generates at least one output based
upon the facts. As used herein, the neural network 3860 maintains
at list of synapses, each with at least one synaptic state and a
list of neural connections between the synapses. The neural network
3860 may respond to stimulus of one or more of the synapses by
transfers through the neural connections that in turn may alter the
synaptic states of some of the synapses.
FIG. 23 shows a flowchart of the program system 3500 of FIG. 21
including at least one of the shown program steps.
Program step 3502 supports operating the micro-radar 3100 by
control of the first DAC output 3110 and/or the second DAC output
3112.
Program step 3504 supports calibrating the first DAC output 3110
based upon the duty cycle estimate 3012 to insure the frequency
3162 of the IF signal 3160. Note that this program step may be used
to help calibrate the second DAC output 3112, by measuring the duty
cycle of the reception signal 3220 with another ADC 3020 input.
This program step may by executed every so often, possibly every
few seconds or minutes, to compensate for temperature 3125 or other
ambient condition changes.
Program step 3506 supports calibrating the second DAC output 3112
to insure the time interval 3350 sweeps between the short delay
3330 and the long delay 3332.
Program step 3508 supports receiving the IF Signal 3106 to generate
one or more ADC readings 3016 and/or an estimated sweep delay Tm
for the object 3020.
Program step 3510 supports estimating the distance based upon the
estimated sweep delay Tm to generate the estimated distance T0 as
shown in FIG. 21.
Program step 3510 may be executed by a computer in any of the
sensor nodes 3600 and/or 3650, the processor 3800, the access point
3700, and/or the server 3750. However, another approach may be to
generate 3512 and send 3514 at least one report 3620 as shown in
FIG. 21, which is then used as the basis of response for a
system.
Program step 3512 supports generating the report 3620 based upon
the one or more ADC readings 3016 and/or the estimate sweep delay
Tm.
Program step 3514 supports sending the report 3620, which in
various embodiments may be targeted for the access point 3700, the
server 3750 and/or the processor 3800. The report may be sent from
the wireless sensor node 3600 and/or from the write sensor node
3650. Depending upon the communications technology employed in the
sending, the report 3620 may be implemented as one or more packets,
frames or encoded in a data stream.
Program step 3516 supports responding to the report 3620 by sending
a version of the report to the processor 3800.
Program step 3518 supports a second responding to the report 3620
and/or a version of the report to estimate the distance T0 of the
object 3620.
Program step 3520 supports a third responding to the report 3620
and/or a version of the report to estimate the size 3028 of the
object 3020, which may be the length of a truck 3024 in some
embodiments.
Note that the report 3620 and/or one of the versions of the report
may include the distance estimate T0 and/or the size estimate 3028
of the object 3020 in some embodiments.
Program step 3522 supports a fourth responding to the report 3620
and/or a version of the report by updating a system and/or system
component. Consider for the moment the systems and/or components
shown in FIG. 24. Any of the processor 3800, the access point 3700,
and/or the server 3750 may be updated. In some embodiments, the
wireless sensor node 3600 and/or the wireline sensor node 3650
and/or one of the sensor processors 3000 may be updated. Also, a
traffic monitoring system 3900, a traffic control system 3902, a
parking management system 180 and/or a production management system
3906 may be updated.
Returning to FIG. 23, program step 3524 supports compensating for
the temperature 3125 shown in FIG. 14 in operating the micro-radar
3100, often by altering the first DAC output 3110 and/or the second
DAC output 3112. This supports what the inventor has experimentally
found to be the operational reality of the components of the
micro-radar, as opposed to the temperature immunity of the antenna
output 3122 and the RF reflection 3124 reported by the prior
art.
The duty cycle estimate 3012 may be based upon measuring the output
of the sharp threshold device 3258 and/or 3268 (for example as a
comparator 3280) corresponds directly to the operating point of the
RC curve. That means that adjusting the duty cycle higher, moves
the operating range of the comparator to a lower (faster moving)
part of the RC curve which in turn reduces the IF frequency 3162.
It was found out experimentally that operating at a 70% duty cycle
corresponds to approximately a 6.5 KHz IF frequency. The first step
in the calibration process then is to adjust the DACs 3010 to
measure a 70% duty cycle on the output.
The temperature 3125 may affect the IF signal 3160 in a couple of
ways. First, the threshold offsets of the sharp threshold devices
3258 and 3268 may vary with temperature causing a time shift
between the transmit pulse 3212 and the reception pulse 3222.
Second, the noise of the IF signal 3160 may increase as the
temperature 3125 increases.
The time shift variation between the transmit pulse 3212 and the
reception pulse 3222 may be eliminated by occasionally performing
calibration radar sweeps supported by program step 3506, which
sample the leading edge of the big bang using the second DAC output
3112 measured during calibration. A feedback loop is implemented in
firmware to adjust the DAC such that the leading edge of the big
bang is fixed to the same value it had during calibration. The DAC
offset from its calibrated value is then filtered (to smooth
operation) and applied to the DAC value used during normal
operation of the micro-radar 3100.
Eliminating the noise in the IF signal 3160 may not be practical.
However, the influence of the extra noise may be used during
detection to adjust a detection threshold 3011. While noise
increases with increased temperature 3125, the radar return signal,
or RF reflection 3124 does not. In certain situations, adjusting
DAC 3010 thresholds to temperature 3125 may improve sensitivity at
low temperatures, which may not be the desired effect. Also, as
temperatures 3125 lower the micro-radar 3100 might uncover return
signals that do not scale with temperature. A method for measuring
the background noise would allow its effects to be corrected. One
method may be to measure temperature 3125 and apply a log scale
factor that is linear if noise is measured in decibels (dB).
In order to reduce the power consumption of the micro-radar 3100,
the sensor processor only needs to listen for the RF reflection
3124 after the initial Rx/Tx overlapping period, called the big
bang.
Adjusting the second DAC output 3112 may advance or delay the
reception signal 3220 when compared to the transmit signal 3210.
Experimentally it was determined that there is a near linear
relationship between the offset time DAC setting and that the
leading edge of the big bang. The leading edge of the big bang may
act as a useful timing reference, because it is not influenced by
the RF reflections 3124 of the micro-radar 3100. Measuring the
leading location of the big bang 3352 at two different duty cycles
3012 can support computing the second DAC output 3112 that will set
the big bang before the start of the time interval 3350 of the time
interval 3300 as shown in FIG. 2B.
The calibration steps 3504 and 3506 create an initial setting of
the first DAC output 3110 for the transmit pulse 3212 and the
second DAC output 3112 for reception pulse 3222 for use in normal
operation and a second setting of the second DAC output that
corresponds to setting the leading edge of the big bang at a fixed
time location (currently 64 samples). This last value may be used
by the temperature compensation algorithm denoted as program step
3524.
The input to the detection algorithm 3526 may be 512 samples at 40
micro-seconds per sample for a total time of 20.48
milliseconds.
In order to improve the signal to noise ratio (SNR) for the
detection step 3526, sampling the IF signal 3160 may be divided
into time segments, each 32 samples long. It was experimentally
found that better results could be obtained if the segments overlap
by 16 samples. This leads to one complete scan being split into 31
bins of 32 samples each. The energy of the IF signal in each bin is
then computed by first subtracting the average (DC) component of
the IF signal and then computing the sum of the squares of the
samples. A single average is computed for all bins, based on that
part of the sweep that is past the influence of the big bang. In
some modes of operation of the sensor processor 3000 may present
the value of each bin in dB for test and debugging purposes. For
detection 3526, a separate baseline may be computed for each bin. A
threshold may then computed based on this baseline.
For motion detection 3526 of the object 3020, often 32
non-overlapping 32 sample bins may be used. Motion is detected by
subtracting the raw samples of one radar sweep from a previous
sweep. This has a couple of nice features: the average value of the
difference is zero so that average need not be computed or
subtracted before energy is computed, and the big bang signal
present in the data is also subtracted so that the sensitivity is
constant across the sweep. For motion detection the detection
threshold 3011 may be used for all bins.
Program step 3528 supports operating the first DAC output 3110 and
the second DAC output 3112 to insure that the sweep delay Tm
corresponds to a specific distance T0.
Program step 3530 supports second operating the first DAC output
3110 and the second DAC output 3112 to insure the IF signal 3160
results from no received RF reflection 3124, so that the IF signal
results from the background noise 3354 as shown in FIG. 2B to
create the background noise estimate 3013 shown in FIG. 14.
Program step 3532 supports using the background noise estimate 3013
to adjust the detect threshold 3011 shown in FIG. 14. The detect
threshold is then used in program step 3526 to detect the object
3020, particularly when it is moving as discussed above.
FIG. 24 shows a simplified network diagram of various systems that
may include one or more communicative couplings 3642 and/or 3652 to
the micro-radar 3100 and/or 3100-2, the superheterodyne radar 916
and/or 916-2, and/or the homodyne radar 918 and/or 918-2 and/or the
wireless sensor node 3600 and/or the wireline sensor node 3650
and/or the processor 3800 and/or the access point 3700 and/or the
server 3750. The various systems include but are not limited to a
traffic monitoring system 3900, a traffic control system 3902, a
parking management system 180 and/or a production management system
3906. Note that the second micro-radar 3100-2 may be used to
estimate the distance T0 to the object 3020, which may be the
surface of a filling 3028 in a chamber of the truck 3024, to
determine how full it is of grapes or oranges, for example.
The preceding discussion serves to provide examples of the
embodiments and is not meant to constrain the scope of the
following claims.
* * * * *